gcc: Refactor treatment of configure flags

Previously configureFlags was defined as one giant interpolated string.
Here we refactor this definition to instead use the usual stdenv string
combinators. This seems more in-line with the average nixpkgs expression
and it seems a bit more natural to things of these as lists of flags
rather than monolithic strings.

7 files changed, 1196 insertions, 1153 deletions

diff --git a/pkgs/development/compilers/gcc/4.5/default.nix b/pkgs/development/compilers/gcc/4.5/default.nix
index e7b188ad71b..69022c2aa3d 100644
--- a/pkgs/development/compilers/gcc/4.5/default.nix
+++ b/pkgs/development/compilers/gcc/4.5/default.nix
@@ -67,55 +67,53 @@ let version = "4.5.4";
     gccArch = stdenv.lib.attrByPath [ "gcc" "arch" ] null targetPlatform;
     gccCpu = stdenv.lib.attrByPath [ "gcc" "cpu" ] null targetPlatform;
     gccAbi = stdenv.lib.attrByPath [ "gcc" "abi" ] null targetPlatform;
-    withArch = if gccArch != null then " --with-arch=${gccArch}" else "";
-    withCpu = if gccCpu != null then " --with-cpu=${gccCpu}" else "";
-    withAbi = if gccAbi != null then " --with-abi=${gccAbi}" else "";
     crossMingw = (targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt");
 
     crossConfigureFlags =
-      withArch +
-      withCpu +
-      withAbi +
+      optional (gccArch != null) "--with-arch=${gccArch}" ++
+      optional (gccCpu != null) "--with-cpu=${gccCpu}" ++
+      optional (gccAbi != null) "--with-abi=${gccAbi}" ++
       # Ensure that -print-prog-name is able to find the correct programs.
-      " --with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as" +
-      " --with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" +
-      (if crossMingw && crossStageStatic then
-        " --with-headers=${libcCross}/include" +
-        " --with-gcc" +
-        " --with-gnu-as" +
-        " --with-gnu-ld" +
-        " --with-gnu-ld" +
-        " --disable-shared" +
-        " --disable-nls" +
-        " --disable-debug" +
-        " --enable-sjlj-exceptions" +
-        " --enable-threads=win32" +
-        " --disable-win32-registry"
-        else if crossStageStatic then
-        " --disable-libssp --disable-nls" +
-        " --without-headers" +
-        " --disable-threads " +
-        " --disable-libmudflap " +
-        " --disable-libgomp " +
-        " --disable-shared" +
-        " --disable-decimal-float" # libdecnumber requires libc
-        else
-        " --with-headers=${libcCross}/include" +
-        " --enable-__cxa_atexit" +
-        " --enable-long-long" +
-        (if crossMingw then
-          " --enable-threads=win32" +
-          " --enable-sjlj-exceptions" +
-          " --enable-hash-synchronization" +
-          " --enable-version-specific-runtime-libs" +
-          " --disable-libssp" +
-          " --disable-nls" +
-          " --with-dwarf2"
-          else
-          " --enable-threads=posix" +
-          " --enable-nls" +
-          " --disable-decimal-float") # No final libdecnumber (it may work only in 386)
-        );
+      [ " --with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as"
+        " --with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" ] ++
+      (if crossMingw && crossStageStatic then [
+        "--with-headers=${libcCross}/include"
+        "--with-gcc"
+        "--with-gnu-as"
+        "--with-gnu-ld"
+        "--with-gnu-ld"
+        "--disable-shared"
+        "--disable-nls"
+        "--disable-debug"
+        "--enable-sjlj-exceptions"
+        "--enable-threads=win32"
+        "--disable-win32-registry"
+        ] else if crossStageStatic then [
+        "--disable-libssp --disable-nls"
+        "--without-headers"
+        "--disable-threads"
+        "--disable-libmudflap"
+        "--disable-libgomp "
+        "--disable-shared"
+        "--disable-decimal-float" # libdecnumber requires libc
+        ] else [
+        "--with-headers=${libcCross}/include"
+        "--enable-__cxa_atexit"
+        "--enable-long-long"
+        ] ++ (if crossMingw then [
+          "--enable-threads=win32"
+          "--enable-sjlj-exceptions"
+          "--enable-hash-synchronization"
+          "--enable-version-specific-runtime-libs"
+          "--disable-libssp"
+          "--disable-nls"
+          "--with-dwarf2"
+          ] else [
+          "--enable-threads=posix"
+          "--enable-nls"
+          "--disable-decimal-float"
+        ]) # No final libdecnumber (it may work only in 386)
+      );
     stageNameAddon = if crossStageStatic then "-stage-static" else
       "-stage-final";
     crossNameAddon = if targetPlatform != hostPlatform then "-${targetPlatform.config}" + stageNameAddon else "";
@@ -241,44 +239,61 @@ stdenv.mkDerivation ({
     then []
     else [ "build" "host" ] ++ stdenv.lib.optional (targetPlatform != hostPlatform) "target";
 
-  configureFlags = "
-    ${if enableMultilib then "" else "--disable-multilib"}
-    ${if enableShared then "" else "--disable-shared"}
-    ${if ppl != null then "--with-ppl=${ppl}" else ""}
-    ${if cloogppl != null then "--with-cloog=${cloogppl}" else ""}
-    ${if langJava then
-      "--with-ecj-jar=${javaEcj} " +
+  configureFlags =
+    # Basic dependencies
+    [
+      "--with-gmp=${gmp.dev}"
+      "--with-mpfr=${mpfr.dev}"
+      "--with-mpc=${libmpc}"
+    ] ++
+    optional (libelf != null) "--with-libelf=${libelf}" ++
+
+    # Basic configuration
+    [
+      "--disable-libstdcxx-pch"
+      "--without-included-gettext"
+      "--with-system-zlib"
+      "--enable-languages=${
+        concatStrings (intersperse ","
+          (  optional langC        "c"
+          ++ optional langCC       "c++"
+          ++ optional langFortran  "fortran"
+          ++ optional langJava     "java"
+          ++ optional langAda      "ada"
+          ++ optional langVhdl     "vhdl"
+          )
+        )
+      }"
+    ] ++
+    optional (!enableMultilib) "--disable-multilib" ++
+    optional (!enableShared) "--disable-shared" ++
+
+    # Optional features
+    optional (cloogppl != null) "--with-cloog=${cloogppl}" ++
+    optional (ppl != null) "--with-ppl=${ppl}" ++
+
+    # Java options
+    optionals langJava [
+      "--with-ecj-jar=${javaEcj} "
 
       # Follow Sun's layout for the convenience of IcedTea/OpenJDK.  See
       # <http://mail.openjdk.java.net/pipermail/distro-pkg-dev/2010-April/008888.html>.
       "--enable-java-home --with-java-home=\${prefix}/lib/jvm/jre "
-      else ""}
-    ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-    ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr}" else ""}
-    --with-gmp=${gmp.dev}
-    --with-mpfr=${mpfr.dev}
-    --with-mpc=${libmpc}
-    ${if libelf != null then "--with-libelf=${libelf}" else ""}
-    --disable-libstdcxx-pch
-    --without-included-gettext
-    --with-system-zlib
-    --enable-languages=${
-      concatStrings (intersperse ","
-        (  optional langC        "c"
-        ++ optional langCC       "c++"
-        ++ optional langFortran  "fortran"
-        ++ optional langJava     "java"
-        ++ optional langAda      "ada"
-        ++ optional langVhdl     "vhdl"
-        )
-      )
-    }
-    ${ # Trick that should be taken out once we have a mips64el-linux not loongson2f
-      if targetPlatform == hostPlatform && stdenv.system == "mips64el-linux" then "--with-arch=loongson2f" else ""}
-    ${if langAda then " --enable-libada" else ""}
-    ${if targetPlatform == hostPlatform && targetPlatform.isi686 then "--with-arch=i686" else ""}
-    ${if targetPlatform != hostPlatform then crossConfigureFlags else ""}
-  ";
+    ] ++
+    optional javaAwtGtk "--enable-java-awt=gtk" ++
+    optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr}" ++
+
+    # Ada
+    optional langAda "--enable-libada" ++
+
+    # Cross-compilation
+    optional (targetPlatform != hostPlatform) crossConfigureFlags ++
+
+    # Platform-specific flags
+    optional (targetPlatform == hostPlatform && targetPlatform.isi686) "--with-arch=i686" ++
+    # Trick that should be taken out once we have a mips64el-linux not loongson2f
+    optional (targetPlatform == hostPlatform && stdenv.system == "mips64el-linux") "--with-arch=loongson2f"
+  ;
 
   targetConfig = if targetPlatform != hostPlatform then targetPlatform.config else null;
 
@@ -295,37 +310,41 @@ stdenv.mkDerivation ({
     # If we are making a cross compiler, cross != null
     NIX_CC_CROSS = optionalString (targetPlatform == hostPlatform) builtins.toString stdenv.cc;
     dontStrip = true;
-    configureFlags = ''
-      ${if enableMultilib then "" else "--disable-multilib"}
-      ${if enableShared then "" else "--disable-shared"}
-      ${if ppl != null then "--with-ppl=${ppl.crossDrv}" else ""}
-      ${if cloogppl != null then "--with-cloog=${cloogppl.crossDrv}" else ""}
-      ${if langJava then "--with-ecj-jar=${javaEcj.crossDrv}" else ""}
-      ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-      ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr.crossDrv}" else ""}
-      --with-gmp=${gmp.crossDrv}
-      --with-mpfr=${mpfr.crossDrv}
-      --with-mpc=${libmpc.crossDrv}
-      --disable-libstdcxx-pch
-      --without-included-gettext
-      --with-system-zlib
-      --enable-languages=${
-        concatStrings (intersperse ","
-          (  optional langC        "c"
-          ++ optional langCC       "c++"
-          ++ optional langFortran  "fortran"
-          ++ optional langJava     "java"
-          ++ optional langAda      "ada"
-          ++ optional langVhdl     "vhdl"
+    configureFlags =
+      optional (!enableMultilib) "--disable-multilib" ++
+      optional (!enableShared) "--disable-shared" ++
+      optional langJava "--with-ecj-jar=${javaEcj.crossDrv}" ++
+      optional javaAwtGtk "--enable-java-awt=gtk" ++
+      optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr.crossDrv}" ++
+      optional (ppl != null) "--with-ppl=${ppl.crossDrv}" ++
+      optional (cloogppl != null) "--with-cloog=${cloogppl.crossDrv}" ++
+
+      [
+        "--with-gmp=${gmp.crossDrv}"
+        "--with-mpfr=${mpfr.crossDrv}"
+        "--with-mpc=${libmpc.crossDrv}"
+        "--disable-libstdcxx-pch"
+        "--without-included-gettext"
+        "--with-system-zlib"
+        "--enable-languages=${
+          concatStrings (intersperse ","
+            (  optional langC        "c"
+            ++ optional langCC       "c++"
+            ++ optional langFortran  "fortran"
+            ++ optional langJava     "java"
+            ++ optional langAda      "ada"
+            ++ optional langVhdl     "vhdl"
+            ++ optional langGo       "go"
+            )
           )
-        )
-      }
-      ${if langAda then " --enable-libada" else ""}
-      ${if targetplatform == hostPlatform && targetPlatform.isi686 then "--with-arch=i686" else ""}
-      ${if targetPlatform != hostPlatform then crossConfigureFlags else ""}
-    '';
+        }"
+      ] ++
+      optional langAda "--enable-libada" ++
+      optional (targetPlatform == hostPlatform && targetPlatform.isi686) "--with-arch=i686" ++
+      optional (targetPlatform != hostPlatform) crossConfigureFlags
+    ;
   };
- 
+
 
   # Needed for the cross compilation to work
   AR = "ar";
diff --git a/pkgs/development/compilers/gcc/4.8/default.nix b/pkgs/development/compilers/gcc/4.8/default.nix
index ab91528049c..7cba8296d83 100644
--- a/pkgs/development/compilers/gcc/4.8/default.nix
+++ b/pkgs/development/compilers/gcc/4.8/default.nix
@@ -108,102 +108,83 @@ let version = "4.8.5";
     javaAwtGtk = langJava && x11Support;
 
     /* Platform flags */
-    platformFlags = let
-        gccArch = stdenv.platform.gcc.arch or null;
-        gccCpu = stdenv.platform.gcc.cpu or null;
-        gccAbi = stdenv.platform.gcc.abi or null;
-        gccFpu = stdenv.platform.gcc.fpu or null;
-        gccFloat = stdenv.platform.gcc.float or null;
-        gccMode = stdenv.platform.gcc.mode or null;
-        withArch = if gccArch != null then " --with-arch=${gccArch}" else "";
-        withCpu = if gccCpu != null then " --with-cpu=${gccCpu}" else "";
-        withAbi = if gccAbi != null then " --with-abi=${gccAbi}" else "";
-        withFpu = if gccFpu != null then " --with-fpu=${gccFpu}" else "";
-        withFloat = if gccFloat != null then " --with-float=${gccFloat}" else "";
-        withMode = if gccMode != null then " --with-mode=${gccMode}" else "";
-      in
-        withArch +
-        withCpu +
-        withAbi +
-        withFpu +
-        withFloat +
-        withMode;
-
-    /* Cross-gcc settings */
+    mkPlatformFlags = platform: let
+        gccArch = platform.gcc.arch or null;
+        gccCpu = platform.gcc.cpu or null;
+        gccAbi = platform.gcc.abi or null;
+        gccFpu = platform.gcc.fpu or null;
+        gccFloat = platform.gcc.float or null;
+        gccMode = platform.gcc.mode or null;
+     in
+        optional (gccArch != null) "--with-arch=${gccArch}" ++
+        optional (gccCpu != null) "--with-cpu=${gccCpu}" ++
+        optional (gccAbi != null) "--with-abi=${gccAbi}" ++
+        optional (gccFpu != null) "--with-fpu=${gccFpu}" ++
+        optional (gccFloat != null) "--with-float=${gccFloat}" ++
+        optional (gccMode != null) "--with-mode=${gccMode}";
+
+    /* Cross-gcc settings (build == host != target) */
+    /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
     crossDarwin = targetPlatform != hostPlatform && targetPlatform.libc == "libSystem";
-    crossConfigureFlags = let
-        gccArch = targetPlatform.gcc.arch or null;
-        gccCpu = targetPlatform.gcc.cpu or null;
-        gccAbi = targetPlatform.gcc.abi or null;
-        gccFpu = targetPlatform.gcc.fpu or null;
-        gccFloat = targetPlatform.gcc.float or null;
-        gccMode = targetPlatform.gcc.mode or null;
-        withArch = if gccArch != null then " --with-arch=${gccArch}" else "";
-        withCpu = if gccCpu != null then " --with-cpu=${gccCpu}" else "";
-        withAbi = if gccAbi != null then " --with-abi=${gccAbi}" else "";
-        withFpu = if gccFpu != null then " --with-fpu=${gccFpu}" else "";
-        withFloat = if gccFloat != null then " --with-float=${gccFloat}" else "";
-        withMode = if gccMode != null then " --with-mode=${gccMode}" else "";
-      in
-        withArch +
-        withCpu +
-        withAbi +
-        withFpu +
-        withFloat +
-        withMode +
+    crossConfigureFlags =
+        mkPlatformFlags targetPlatform ++
+
         # Ensure that -print-prog-name is able to find the correct programs.
-        " --with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as" +
-        " --with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" +
+        [ "--with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as"
+          "--with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" ] ++
         (if crossMingw && crossStageStatic then
-          " --with-headers=${libcCross}/include" +
-          " --with-gcc" +
-          " --with-gnu-as" +
-          " --with-gnu-ld" +
-          " --with-gnu-ld" +
-          " --disable-shared" +
-          " --disable-nls" +
-          " --disable-debug" +
-          " --enable-sjlj-exceptions" +
-          " --enable-threads=win32" +
-          " --disable-win32-registry"
-          else if crossStageStatic then
-          " --disable-libssp --disable-nls" +
-          " --without-headers" +
-          " --disable-threads " +
-          " --disable-libmudflap " +
-          " --disable-libgomp " +
-          " --disable-libquadmath" +
-          " --disable-shared" +
-          " --disable-libatomic " +  # libatomic requires libc
-          " --disable-decimal-float" # libdecnumber requires libc
-          else
-          (if crossDarwin then " --with-sysroot=${libcCross.out}/share/sysroot"
-           else                " --with-headers=${libcCross.dev}/include") +
-          # Ensure that -print-prog-name is able to find the correct programs.
-          " --enable-__cxa_atexit" +
-          " --enable-long-long" +
-          (if crossMingw then
-            " --enable-threads=win32" +
-            " --enable-sjlj-exceptions" +
-            " --enable-hash-synchronization" +
-            " --disable-libssp" +
-            " --disable-nls" +
-            " --with-dwarf2" +
+          [ "--with-headers=${libcCross}/include"
+            "--with-gcc"
+            "--with-gnu-as"
+            "--with-gnu-ld"
+            "--with-gnu-ld"
+            "--disable-shared"
+            "--disable-nls"
+            "--disable-debug"
+            "--enable-sjlj-exceptions"
+            "--enable-threads=win32"
+            "--disable-win32-registry"
+          ] else if crossStageStatic then
+          [ "--disable-libssp --disable-nls"
+            "--without-headers"
+            "--disable-threads "
+            "--disable-libgomp "
+            "--disable-libquadmath"
+            "--disable-shared"
+            "--disable-libatomic "  # libatomic requires libc
+            "--disable-decimal-float" # libdecnumber requires libc
+          ] else
+            (if crossDarwin then ["--with-sysroot=${getLib libcCross}/share/sysroot"]
+             else                ["--with-headers=${getDev libcCross}/include"]) ++
+          [ "--enable-__cxa_atexit"
+            "--enable-long-long"
+          ] ++
+          (if crossMingw then [
+            "--enable-threads=win32"
+            "--enable-sjlj-exceptions"
+            "--enable-hash-synchronization"
+            "--disable-libssp"
+            "--disable-nls"
+            "--with-dwarf2"
             # I think noone uses shared gcc libs in mingw, so we better do the same.
             # In any case, mingw32 g++ linking is broken by default with shared libs,
             # unless adding "-lsupc++" to any linking command. I don't know why.
-            " --disable-shared" +
+            "--disable-shared"
             # To keep ABI compatibility with upstream mingw-w64
-            " --enable-fully-dynamic-string"
-            else (if targetPlatform.libc == "uclibc" then
+            "--enable-fully-dynamic-string"
+          ] else
+            optionals (targetPlatform.libc == "uclibc") [
               # In uclibc cases, libgomp needs an additional '-ldl'
               # and as I don't know how to pass it, I disable libgomp.
-              " --disable-libgomp" else "") +
-            " --enable-threads=posix" +
-            " --enable-nls" +
-            " --disable-decimal-float") # No final libdecnumber (it may work only in 386)
-          );
+              "--disable-libgomp"
+            ] ++
+            [ "--enable-threads=posix"
+              "--enable-nls"
+              "--disable-decimal-float" # No final libdecnumber (it may work only in 386)
+            ]
+          )
+        );
     stageNameAddon = if crossStageStatic then "-stage-static" else "-stage-final";
     crossNameAddon = if targetPlatform != hostPlatform then "-${targetPlatform.config}" + stageNameAddon else "";
 
@@ -329,63 +310,87 @@ stdenv.mkDerivation ({
     then []
     else [ "build" "host" ] ++ stdenv.lib.optional (targetPlatform != hostPlatform) "target";
 
-  configureFlags = "
-    ${if hostPlatform.isSunOS then
-      " --enable-long-long --enable-libssp --enable-threads=posix --disable-nls --enable-__cxa_atexit " +
-      # On Illumos/Solaris GNU as is preferred
-      " --with-gnu-as --without-gnu-ld "
-      else ""}
-    --enable-lto
-    ${if enableMultilib then "--disable-libquadmath" else "--disable-multilib"}
-    ${if enableShared then "" else "--disable-shared"}
-    ${if enablePlugin then "--enable-plugin" else "--disable-plugin"}
-    ${optionalString (isl != null) "--with-isl=${isl}"}
-    ${optionalString (cloog != null) "--with-cloog=${cloog} --disable-cloog-version-check --enable-cloog-backend=isl"}
-    ${if langJava then
-      "--with-ecj-jar=${javaEcj} " +
+  configureFlags =
+    # Basic dependencies
+    [
+      "--with-gmp-include=${gmp.dev}/include"
+      "--with-gmp-lib=${gmp.out}/lib"
+      "--with-mpfr-include=${mpfr.dev}/include"
+      "--with-mpfr-lib=${mpfr.out}/lib"
+      "--with-mpc=${libmpc}"
+    ] ++
+    optional (libelf != null) "--with-libelf=${libelf}" ++
+
+    # Basic configuration
+    [
+      "--enable-lto"
+      "--disable-libstdcxx-pch"
+      "--without-included-gettext"
+      "--with-system-zlib"
+      "--enable-static"
+      "--enable-languages=${
+        concatStrings (intersperse ","
+          (  optional langC        "c"
+          ++ optional langCC       "c++"
+          ++ optional langFortran  "fortran"
+          ++ optional langJava     "java"
+          ++ optional langAda      "ada"
+          ++ optional langVhdl     "vhdl"
+          ++ optional langGo       "go"
+          ++ optional langObjC     "objc"
+          ++ optional langObjCpp   "obj-c++"
+          ++ optionals crossDarwin [ "objc" "obj-c++" ]
+          )
+        )
+      }"
+    ] ++
+
+    # Optional features
+    optional (isl != null) "--with-isl=${isl}" ++
+    optional (cloog != null) "--with-cloog=${cloog} --disable-cloog-version-check --enable-cloog-backend=isl" ++
+
+    (if enableMultilib
+      then ["--enable-multilib" "--disable-libquadmath"]
+      else ["--disable-multilib"]) ++
+    optional (!enableShared) "--disable-shared" ++
+    (if enablePlugin
+      then ["--enable-plugin"]
+      else ["--disable-plugin"]) ++
+
+    # Java options
+    optionals langJava [
+      "--with-ecj-jar=${javaEcj} "
 
       # Follow Sun's layout for the convenience of IcedTea/OpenJDK.  See
       # <http://mail.openjdk.java.net/pipermail/distro-pkg-dev/2010-April/008888.html>.
       "--enable-java-home --with-java-home=\${prefix}/lib/jvm/jre "
-      else ""}
-    ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-    ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr}" else ""}
-    --with-gmp-include=${gmp.dev}/include
-    --with-gmp-lib=${gmp.out}/lib
-    --with-mpfr-include=${mpfr.dev}/include
-    --with-mpfr-lib=${mpfr.out}/lib
-    --with-mpc=${libmpc}
-    ${if libelf != null then "--with-libelf=${libelf}" else ""}
-    --disable-libstdcxx-pch
-    --without-included-gettext
-    --with-system-zlib
-    --enable-static
-    --enable-languages=${
-      concatStrings (intersperse ","
-        (  optional langC        "c"
-        ++ optional langCC       "c++"
-        ++ optional langFortran  "fortran"
-        ++ optional langJava     "java"
-        ++ optional langAda      "ada"
-        ++ optional langVhdl     "vhdl"
-        ++ optional langGo       "go"
-        ++ optional langObjC     "objc"
-        ++ optional langObjCpp   "obj-c++"
-        ++ optionals crossDarwin [ "objc" "obj-c++" ]
-        )
-      )
-    }
-    ${if targetPlatform == hostPlatform
-      then if hostPlatform.isDarwin
-        then " --with-native-system-header-dir=${darwin.usr-include}"
-        else " --with-native-system-header-dir=${getDev stdenv.cc.libc}/include"
-      else ""}
-    ${if langAda then " --enable-libada" else ""}
-    ${if targetPlatform == hostPlatform && targetPlatform.isi686 then "--with-arch=i686" else ""}
-    ${if targetPlatform != hostPlatform then crossConfigureFlags else ""}
-    ${if !bootstrap then "--disable-bootstrap" else ""}
-    ${if targetPlatform == hostPlatform then platformFlags else ""}
-  ";
+    ] ++
+    optional javaAwtGtk "--enable-java-awt=gtk" ++
+    optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr}" ++
+
+    # Ada
+    optional langAda "--enable-libada" ++
+
+    # Cross-compilation
+    optional (targetPlatform == hostPlatform) (
+      let incDir = if hostPlatform.isDarwin
+                     then "${darwin.usr-include}"
+                     else "${getDev stdenv.cc.libc}/include";
+      in "--with-native-system-header-dir=${incDir}"
+    ) ++
+
+    optional (targetPlatform == hostPlatform) (mkPlatformFlags stdenv.platform) ++
+    optional (targetPlatform != hostPlatform) crossConfigureFlags ++
+    optional (!bootstrap) "--disable-bootstrap" ++
+
+    # Platform-specific flags
+    optional (targetPlatform == hostPlatform && targetPlatform.isi686) "--with-arch=i686" ++
+    optionals hostPlatform.isSunOS [
+      "--enable-long-long --enable-libssp --enable-threads=posix --disable-nls --enable-__cxa_atexit"
+      # On Illumos/Solaris GNU as is preferred
+      "--with-gnu-as --without-gnu-ld"
+    ]
+  ;
 
   targetConfig = if targetPlatform != hostPlatform then targetPlatform.config else null;
 
@@ -404,11 +409,6 @@ stdenv.mkDerivation ({
     xgccAbi = targetPlatform.gcc.abi or null;
     xgccFpu = targetPlatform.gcc.fpu or null;
     xgccFloat = targetPlatform.gcc.float or null;
-    xwithArch = if xgccArch != null then " --with-arch=${xgccArch}" else "";
-    xwithCpu = if xgccCpu != null then " --with-cpu=${xgccCpu}" else "";
-    xwithAbi = if xgccAbi != null then " --with-abi=${xgccAbi}" else "";
-    xwithFpu = if xgccFpu != null then " --with-fpu=${xgccFpu}" else "";
-    xwithFloat = if xgccFloat != null then " --with-float=${xgccFloat}" else "";
   in {
     AR = "${targetPlatform.config}-ar";
     LD = "${targetPlatform.config}-ld";
@@ -422,38 +422,40 @@ stdenv.mkDerivation ({
     # If we are making a cross compiler, cross != null
     NIX_CC_CROSS = optionalString (targetPlatform == hostPlatform) builtins.toString stdenv.cc;
     dontStrip = true;
-    configureFlags = ''
-      ${if enableMultilib then "" else "--disable-multilib"}
-      ${if enableShared then "" else "--disable-shared"}
-      ${if cloog != null then "--with-cloog=${cloog.crossDrv} --enable-cloog-backend=isl" else ""}
-      ${if langJava then "--with-ecj-jar=${javaEcj.crossDrv}" else ""}
-      ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-      ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr.crossDrv}" else ""}
-      --with-gmp=${gmp.crossDrv}
-      --with-mpfr=${mpfr.crossDrv}
-      --with-mpc=${libmpc.crossDrv}
-      --disable-libstdcxx-pch
-      --without-included-gettext
-      --with-system-zlib
-      --enable-languages=${
-        concatStrings (intersperse ","
-          (  optional langC        "c"
-          ++ optional langCC       "c++"
-          ++ optional langFortran  "fortran"
-          ++ optional langJava     "java"
-          ++ optional langAda      "ada"
-          ++ optional langVhdl     "vhdl"
-          ++ optional langGo       "go"
+    configureFlags =
+      optional (!enableMultilib) "--disable-multilib" ++
+      optional (!enableShared) "--disable-shared" ++
+      optional langJava "--with-ecj-jar=${javaEcj.crossDrv}" ++
+      optional javaAwtGtk "--enable-java-awt=gtk" ++
+      optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr.crossDrv}" ++
+      optional (cloog != null) "--with-cloog=${cloog.crossDrv} --enable-cloog-backend=isl" ++
+      [
+        "--with-gmp=${gmp.crossDrv}"
+        "--with-mpfr=${mpfr.crossDrv}"
+        "--with-mpc=${libmpc.crossDrv}"
+        "--disable-libstdcxx-pch"
+        "--without-included-gettext"
+        "--with-system-zlib"
+        "--enable-languages=${
+          concatStrings (intersperse ","
+            (  optional langC        "c"
+            ++ optional langCC       "c++"
+            ++ optional langFortran  "fortran"
+            ++ optional langJava     "java"
+            ++ optional langAda      "ada"
+            ++ optional langVhdl     "vhdl"
+            ++ optional langGo       "go"
+            )
           )
-        )
-      }
-      ${if langAda then " --enable-libada" else ""}
-      ${xwithArch}
-      ${xwithCpu}
-      ${xwithAbi}
-      ${xwithFpu}
-      ${xwithFloat}
-    '';
+        }"
+      ] ++
+      optional langAda "--enable-libada" ++
+      optional (xgccArch != null) "--with-arch=${xgccArch}" ++
+      optional (xgccCpu != null) "--with-cpu=${xgccCpu}" ++
+      optional (xgccAbi != null) "--with-abi=${xgccAbi}" ++
+      optional (xgccFpu != null) "--with-fpu=${xgccFpu}" ++
+      optional (xgccFloat != null) "--with-float=${xgccFloat}"
+    ;
     buildFlags = "";
   };
 
diff --git a/pkgs/development/compilers/gcc/4.9/default.nix b/pkgs/development/compilers/gcc/4.9/default.nix
index 794d809fa72..98df530d884 100644
--- a/pkgs/development/compilers/gcc/4.9/default.nix
+++ b/pkgs/development/compilers/gcc/4.9/default.nix
@@ -99,107 +99,90 @@ let version = "4.9.4";
     javaAwtGtk = langJava && x11Support;
 
     /* Platform flags */
-    platformFlags = let
-        gccArch = stdenv.platform.gcc.arch or null;
-        gccCpu = stdenv.platform.gcc.cpu or null;
-        gccAbi = stdenv.platform.gcc.abi or null;
-        gccFpu = stdenv.platform.gcc.fpu or null;
-        gccFloat = stdenv.platform.gcc.float or null;
-        gccMode = stdenv.platform.gcc.mode or null;
-        withArch = if gccArch != null then " --with-arch=${gccArch}" else "";
-        withCpu = if gccCpu != null then " --with-cpu=${gccCpu}" else "";
-        withAbi = if gccAbi != null then " --with-abi=${gccAbi}" else "";
-        withFpu = if gccFpu != null then " --with-fpu=${gccFpu}" else "";
-        withFloat = if gccFloat != null then " --with-float=${gccFloat}" else "";
-        withMode = if gccMode != null then " --with-mode=${gccMode}" else "";
-      in
-        withArch +
-        withCpu +
-        withAbi +
-        withFpu +
-        withFloat +
-        withMode;
-
-    /* Cross-gcc settings */
+    mkPlatformFlags = platform: let
+        gccArch = platform.gcc.arch or null;
+        gccCpu = platform.gcc.cpu or null;
+        gccAbi = platform.gcc.abi or null;
+        gccFpu = platform.gcc.fpu or null;
+        gccFloat = platform.gcc.float or null;
+        gccMode = platform.gcc.mode or null;
+     in
+        optional (gccArch != null) "--with-arch=${gccArch}" ++
+        optional (gccCpu != null) "--with-cpu=${gccCpu}" ++
+        optional (gccAbi != null) "--with-abi=${gccAbi}" ++
+        optional (gccFpu != null) "--with-fpu=${gccFpu}" ++
+        optional (gccFloat != null) "--with-float=${gccFloat}" ++
+        optional (gccMode != null) "--with-mode=${gccMode}";
+
+    /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
     crossDarwin = targetPlatform != hostPlatform && targetPlatform.libc == "libSystem";
-    crossConfigureFlags = let
-        gccArch = targetPlatform.gcc.arch or null;
-        gccCpu = targetPlatform.gcc.cpu or null;
-        gccAbi = targetPlatform.gcc.abi or null;
-        gccFpu = targetPlatform.gcc.fpu or null;
-        gccFloat = targetPlatform.gcc.float or null;
-        gccMode = targetPlatform.gcc.mode or null;
-        withArch = if gccArch != null then " --with-arch=${gccArch}" else "";
-        withCpu = if gccCpu != null then " --with-cpu=${gccCpu}" else "";
-        withAbi = if gccAbi != null then " --with-abi=${gccAbi}" else "";
-        withFpu = if gccFpu != null then " --with-fpu=${gccFpu}" else "";
-        withFloat = if gccFloat != null then " --with-float=${gccFloat}" else "";
-        withMode = if gccMode != null then " --with-mode=${gccMode}" else "";
-      in
-        withArch +
-        withCpu +
-        withAbi +
-        withFpu +
-        withFloat +
-        withMode +
+    crossConfigureFlags =
+        mkPlatformFlags targetPlatform ++
+
         # Ensure that -print-prog-name is able to find the correct programs.
-        " --with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as" +
-        " --with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" +
+        [ "--with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as"
+          "--with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" ] ++
         (if crossMingw && crossStageStatic then
-          " --with-headers=${libcCross}/include" +
-          " --with-gcc" +
-          " --with-gnu-as" +
-          " --with-gnu-ld" +
-          " --with-gnu-ld" +
-          " --disable-shared" +
-          " --disable-nls" +
-          " --disable-debug" +
-          " --enable-sjlj-exceptions" +
-          " --enable-threads=win32" +
-          " --disable-win32-registry"
-          else if crossStageStatic then
-          " --disable-libssp --disable-nls" +
-          " --without-headers" +
-          " --disable-threads " +
-          " --disable-libgomp " +
-          " --disable-libquadmath" +
-          " --disable-shared" +
-          " --disable-libatomic " +  # libatomic requires libc
-          " --disable-decimal-float" # libdecnumber requires libc
-          else
-          (if crossDarwin then " --with-sysroot=${libcCross.out}/share/sysroot"
-           else                " --with-headers=${libcCross.dev}/include") +
-          " --enable-__cxa_atexit" +
-          " --enable-long-long" +
-          (if crossMingw then
-            " --enable-threads=win32" +
-            " --enable-sjlj-exceptions" +
-            " --enable-hash-synchronization" +
-            " --disable-libssp" +
-            " --disable-nls" +
-            " --with-dwarf2" +
+          [ "--with-headers=${libcCross}/include"
+            "--with-gcc"
+            "--with-gnu-as"
+            "--with-gnu-ld"
+            "--with-gnu-ld"
+            "--disable-shared"
+            "--disable-nls"
+            "--disable-debug"
+            "--enable-sjlj-exceptions"
+            "--enable-threads=win32"
+            "--disable-win32-registry"
+          ] else if crossStageStatic then
+          [ "--disable-libssp"
+            "--disable-nls"
+            "--without-headers"
+            "--disable-threads "
+            "--disable-libgomp "
+            "--disable-libquadmath"
+            "--disable-shared"
+            "--disable-libatomic "  # libatomic requires libc
+            "--disable-decimal-float" # libdecnumber requires libc
+          ] else
+            (if crossDarwin then ["--with-sysroot=${getLib libcCross}/share/sysroot"]
+             else                ["--with-headers=${getDev libcCross}/include"]) ++
+          [ "--enable-__cxa_atexit"
+            "--enable-long-long"
+          ] ++
+
+          (if crossMingw then [
+            "--enable-threads=win32"
+            "--enable-sjlj-exceptions"
+            "--enable-hash-synchronization"
+            "--disable-libssp"
+            "--disable-nls"
+            "--with-dwarf2"
             # I think noone uses shared gcc libs in mingw, so we better do the same.
             # In any case, mingw32 g++ linking is broken by default with shared libs,
             # unless adding "-lsupc++" to any linking command. I don't know why.
-            " --disable-shared" +
+            "--disable-shared"
             # To keep ABI compatibility with upstream mingw-w64
-            " --enable-fully-dynamic-string"
-            else (if targetPlatform.libc == "uclibc" then
+            "--enable-fully-dynamic-string"
+          ] else
+            optionals (targetPlatform.libc == "uclibc") [
               # libsanitizer requires netrom/netrom.h which is not
               # available in uclibc.
-              " --disable-libsanitizer" +
+              "--disable-libsanitizer"
               # In uclibc cases, libgomp needs an additional '-ldl'
               # and as I don't know how to pass it, I disable libgomp.
-              " --disable-libgomp" else "") +
-            " --enable-threads=posix" +
-            " --enable-nls" +
-            " --disable-decimal-float") # No final libdecnumber (it may work only in 386)
+              "--disable-libgomp"
+            ] ++
+            [ "--enable-threads=posix"
+              "--enable-nls"
+              "--disable-decimal-float" # No final libdecnumber (it may work only in 386)
+            ])
           );
     stageNameAddon = if crossStageStatic then "-stage-static" else "-stage-final";
     crossNameAddon = if targetPlatform != hostPlatform then "-${targetPlatform.config}" + stageNameAddon else "";
 
-  bootstrap = targetPlatform == hostPlatform;
+    bootstrap = targetPlatform == hostPlatform;
 
 in
 
@@ -326,61 +309,86 @@ stdenv.mkDerivation ({
     then []
     else [ "build" "host" ] ++ stdenv.lib.optional (targetPlatform != hostPlatform) "target";
 
-  configureFlags = "
-    ${if hostPlatform.isSunOS then
-      " --enable-long-long --enable-libssp --enable-threads=posix --disable-nls --enable-__cxa_atexit " +
-      # On Illumos/Solaris GNU as is preferred
-      " --with-gnu-as --without-gnu-ld "
-      else ""}
-    --enable-lto
-    ${if enableMultilib then "--enable-multilib --disable-libquadmath" else "--disable-multilib"}
-    ${if enableShared then "" else "--disable-shared"}
-    ${if enablePlugin then "--enable-plugin" else "--disable-plugin"}
-    ${optionalString (isl != null) "--with-isl=${isl}"}
-    ${optionalString (cloog != null) "--with-cloog=${cloog} --disable-cloog-version-check --enable-cloog-backend=isl"}
-    ${if langJava then
-      "--with-ecj-jar=${javaEcj} " +
+  configureFlags =
+    # Basic dependencies
+    [
+      "--with-gmp-include=${gmp.dev}/include"
+      "--with-gmp-lib=${gmp.out}/lib"
+      "--with-mpfr=${mpfr.dev}"
+      "--with-mpc=${libmpc}"
+    ] ++
+    optional (libelf != null) "--with-libelf=${libelf}" ++
+
+    # Basic configuration
+    [
+      "--enable-lto"
+      "--disable-libstdcxx-pch"
+      "--without-included-gettext"
+      "--with-system-zlib"
+      "--enable-static"
+      "--enable-languages=${
+        concatStrings (intersperse ","
+          (  optional langC        "c"
+          ++ optional langCC       "c++"
+          ++ optional langFortran  "fortran"
+          ++ optional langJava     "java"
+          ++ optional langAda      "ada"
+          ++ optional langVhdl     "vhdl"
+          ++ optional langGo       "go"
+          ++ optional langObjC     "objc"
+          ++ optional langObjCpp   "obj-c++"
+          ++ optionals crossDarwin [ "objc" "obj-c++" ]
+          )
+        )
+      }"
+    ] ++
+
+    (if enableMultilib
+      then ["--enable-multilib" "--disable-libquadmath"]
+      else ["--disable-multilib"]) ++
+    optional (!enableShared) "--disable-shared" ++
+    (if enablePlugin
+      then ["--enable-plugin"]
+      else ["--disable-plugin"]) ++
+
+    # Optional features
+    optional (isl != null) "--with-isl=${isl}" ++
+    optional (cloog != null) "--with-cloog=${cloog} --disable-cloog-version-check --enable-cloog-backend=isl" ++
+
+    # Java options
+    optionals langJava [
+      "--with-ecj-jar=${javaEcj} "
 
       # Follow Sun's layout for the convenience of IcedTea/OpenJDK.  See
       # <http://mail.openjdk.java.net/pipermail/distro-pkg-dev/2010-April/008888.html>.
       "--enable-java-home --with-java-home=\${prefix}/lib/jvm/jre "
-      else ""}
-    ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-    ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr}" else ""}
-    --with-gmp=${gmp.dev}
-    --with-mpfr=${mpfr.dev}
-    --with-mpc=${libmpc}
-    ${if libelf != null then "--with-libelf=${libelf}" else ""}
-    --disable-libstdcxx-pch
-    --without-included-gettext
-    --with-system-zlib
-    --enable-static
-    --enable-languages=${
-      concatStrings (intersperse ","
-        (  optional langC        "c"
-        ++ optional langCC       "c++"
-        ++ optional langFortran  "fortran"
-        ++ optional langJava     "java"
-        ++ optional langAda      "ada"
-        ++ optional langVhdl     "vhdl"
-        ++ optional langGo       "go"
-        ++ optional langObjC     "objc"
-        ++ optional langObjCpp   "obj-c++"
-        ++ optionals crossDarwin [ "objc" "obj-c++" ]
-        )
-      )
-    }
-    ${if targetPlatform == hostPlatform
-      then if hostPlatform.isDarwin
-        then " --with-native-system-header-dir=${darwin.usr-include}"
-        else " --with-native-system-header-dir=${getDev stdenv.cc.libc}/include"
-      else ""}
-    ${if langAda then " --enable-libada" else ""}
-    ${if targetPlatform == hostPlatform && targetPlatform.isi686 then "--with-arch=i686" else ""}
-    ${if targetPlatform != hostPlatform then crossConfigureFlags else ""}
-    ${if !bootstrap then "--disable-bootstrap" else ""}
-    ${if targetPlatform == hostPlatform then platformFlags else ""}
-  ";
+    ] ++
+    optional javaAwtGtk "--enable-java-awt=gtk" ++
+    optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr}" ++
+
+    # Ada
+    optional langAda "--enable-libada" ++
+
+    # Cross-compilation
+    optional (targetPlatform == hostPlatform) (
+      let incDir = if hostPlatform.isDarwin
+                     then "${darwin.usr-include}"
+                     else "${getDev stdenv.cc.libc}/include";
+      in "--with-native-system-header-dir=${incDir}"
+    ) ++
+
+    optional (targetPlatform == hostPlatform) (mkPlatformFlags stdenv.platform) ++
+    optional (targetPlatform != hostPlatform) crossConfigureFlags ++
+    optional (!bootstrap) "--disable-bootstrap" ++
+
+    # Platform-specific flags
+    optional (targetPlatform == hostPlatform && targetPlatform.isi686) "--with-arch=i686" ++
+    optionals hostPlatform.isSunOS [
+      "--enable-long-long --enable-libssp --enable-threads=posix --disable-nls --enable-__cxa_atexit"
+      # On Illumos/Solaris GNU as is preferred
+      "--with-gnu-as --without-gnu-ld"
+    ]
+  ;
 
   targetConfig = if targetPlatform != hostPlatform then targetPlatform.config else null;
 
@@ -393,17 +401,13 @@ stdenv.mkDerivation ({
     then "install-strip"
     else "install";
 
+  /* For cross-built gcc (build != host == target) */
   crossAttrs = let
     xgccArch = targetPlatform.gcc.arch or null;
     xgccCpu = targetPlatform.gcc.cpu or null;
     xgccAbi = targetPlatform.gcc.abi or null;
     xgccFpu = targetPlatform.gcc.fpu or null;
     xgccFloat = targetPlatform.gcc.float or null;
-    xwithArch = if xgccArch != null then " --with-arch=${xgccArch}" else "";
-    xwithCpu = if xgccCpu != null then " --with-cpu=${xgccCpu}" else "";
-    xwithAbi = if xgccAbi != null then " --with-abi=${xgccAbi}" else "";
-    xwithFpu = if xgccFpu != null then " --with-fpu=${xgccFpu}" else "";
-    xwithFloat = if xgccFloat != null then " --with-float=${xgccFloat}" else "";
   in {
     AR = "${targetPlatform.config}-ar";
     LD = "${targetPlatform.config}-ld";
@@ -417,38 +421,40 @@ stdenv.mkDerivation ({
     # If we are making a cross compiler, cross != null
     NIX_CC_CROSS = optionalString (targetPlatform == hostPlatform) builtins.toString stdenv.cc;
     dontStrip = true;
-    configureFlags = ''
-      ${if enableMultilib then "" else "--disable-multilib"}
-      ${if enableShared then "" else "--disable-shared"}
-      ${if cloog != null then "--with-cloog=${cloog.crossDrv} --enable-cloog-backend=isl" else ""}
-      ${if langJava then "--with-ecj-jar=${javaEcj.crossDrv}" else ""}
-      ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-      ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr.crossDrv}" else ""}
-      --with-gmp=${gmp.crossDrv}
-      --with-mpfr=${mpfr.crossDrv}
-      --with-mpc=${libmpc.crossDrv}
-      --disable-libstdcxx-pch
-      --without-included-gettext
-      --with-system-zlib
-      --enable-languages=${
-        concatStrings (intersperse ","
-          (  optional langC        "c"
-          ++ optional langCC       "c++"
-          ++ optional langFortran  "fortran"
-          ++ optional langJava     "java"
-          ++ optional langAda      "ada"
-          ++ optional langVhdl     "vhdl"
-          ++ optional langGo       "go"
+    configureFlags =
+      optional (!enableMultilib) "--disable-multilib" ++
+      optional (!enableShared) "--disable-shared" ++
+      optional langJava "--with-ecj-jar=${javaEcj.crossDrv}" ++
+      optional javaAwtGtk "--enable-java-awt=gtk" ++
+      optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr.crossDrv}" ++
+      optional (cloog != null) "--with-cloog=${cloog.crossDrv} --enable-cloog-backend=isl" ++
+      [
+        "--with-gmp=${gmp.crossDrv}"
+        "--with-mpfr=${mpfr.crossDrv}"
+        "--with-mpc=${libmpc.crossDrv}"
+        "--disable-libstdcxx-pch"
+        "--without-included-gettext"
+        "--with-system-zlib"
+        "--enable-languages=${
+          concatStrings (intersperse ","
+            (  optional langC        "c"
+            ++ optional langCC       "c++"
+            ++ optional langFortran  "fortran"
+            ++ optional langJava     "java"
+            ++ optional langAda      "ada"
+            ++ optional langVhdl     "vhdl"
+            ++ optional langGo       "go"
+            )
           )
-        )
-      }
-      ${if langAda then " --enable-libada" else ""}
-      ${xwithArch}
-      ${xwithCpu}
-      ${xwithAbi}
-      ${xwithFpu}
-      ${xwithFloat}
-    '';
+        }"
+      ] ++
+      optional langAda "--enable-libada" ++
+      optional (xgccArch != null) "--with-arch=${xgccArch}" ++
+      optional (xgccCpu != null) "--with-cpu=${xgccCpu}" ++
+      optional (xgccAbi != null) "--with-abi=${xgccAbi}" ++
+      optional (xgccFpu != null) "--with-fpu=${xgccFpu}" ++
+      optional (xgccFloat != null) "--with-float=${xgccFloat}"
+    ;
     buildFlags = "";
   };
 
diff --git a/pkgs/development/compilers/gcc/5/default.nix b/pkgs/development/compilers/gcc/5/default.nix
index 345e2baf671..fe9735d1fd6 100644
--- a/pkgs/development/compilers/gcc/5/default.nix
+++ b/pkgs/development/compilers/gcc/5/default.nix
@@ -103,107 +103,89 @@ let version = "5.5.0";
     javaAwtGtk = langJava && x11Support;
 
     /* Platform flags */
-    platformFlags = let
-        gccArch = stdenv.platform.gcc.arch or null;
-        gccCpu = stdenv.platform.gcc.cpu or null;
-        gccAbi = stdenv.platform.gcc.abi or null;
-        gccFpu = stdenv.platform.gcc.fpu or null;
-        gccFloat = stdenv.platform.gcc.float or null;
-        gccMode = stdenv.platform.gcc.mode or null;
-        withArch = if gccArch != null then " --with-arch=${gccArch}" else "";
-        withCpu = if gccCpu != null then " --with-cpu=${gccCpu}" else "";
-        withAbi = if gccAbi != null then " --with-abi=${gccAbi}" else "";
-        withFpu = if gccFpu != null then " --with-fpu=${gccFpu}" else "";
-        withFloat = if gccFloat != null then " --with-float=${gccFloat}" else "";
-        withMode = if gccMode != null then " --with-mode=${gccMode}" else "";
-      in
-        withArch +
-        withCpu +
-        withAbi +
-        withFpu +
-        withFloat +
-        withMode;
-
-    /* Cross-gcc settings */
+    mkPlatformFlags = platform: let
+        gccArch = platform.gcc.arch or null;
+        gccCpu = platform.gcc.cpu or null;
+        gccAbi = platform.gcc.abi or null;
+        gccFpu = platform.gcc.fpu or null;
+        gccFloat = platform.gcc.float or null;
+        gccMode = platform.gcc.mode or null;
+     in
+        optional (gccArch != null) "--with-arch=${gccArch}" ++
+        optional (gccCpu != null) "--with-cpu=${gccCpu}" ++
+        optional (gccAbi != null) "--with-abi=${gccAbi}" ++
+        optional (gccFpu != null) "--with-fpu=${gccFpu}" ++
+        optional (gccFloat != null) "--with-float=${gccFloat}" ++
+        optional (gccMode != null) "--with-mode=${gccMode}";
+
+    /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
     crossDarwin = targetPlatform != hostPlatform && targetPlatform.libc == "libSystem";
-    crossConfigureFlags = let
-        gccArch = targetPlatform.gcc.arch or null;
-        gccCpu = targetPlatform.gcc.cpu or null;
-        gccAbi = targetPlatform.gcc.abi or null;
-        gccFpu = targetPlatform.gcc.fpu or null;
-        gccFloat = targetPlatform.gcc.float or null;
-        gccMode = targetPlatform.gcc.mode or null;
-        withArch = if gccArch != null then " --with-arch=${gccArch}" else "";
-        withCpu = if gccCpu != null then " --with-cpu=${gccCpu}" else "";
-        withAbi = if gccAbi != null then " --with-abi=${gccAbi}" else "";
-        withFpu = if gccFpu != null then " --with-fpu=${gccFpu}" else "";
-        withFloat = if gccFloat != null then " --with-float=${gccFloat}" else "";
-        withMode = if gccMode != null then " --with-mode=${gccMode}" else "";
-      in
-        withArch +
-        withCpu +
-        withAbi +
-        withFpu +
-        withFloat +
-        withMode +
+    crossConfigureFlags =
+        mkPlatformFlags targetPlatform ++
+
         # Ensure that -print-prog-name is able to find the correct programs.
-        " --with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as" +
-        " --with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" +
+        [ "--with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as"
+          "--with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" ] ++
         (if crossMingw && crossStageStatic then
-          " --with-headers=${libcCross}/include" +
-          " --with-gcc" +
-          " --with-gnu-as" +
-          " --with-gnu-ld" +
-          " --with-gnu-ld" +
-          " --disable-shared" +
-          " --disable-nls" +
-          " --disable-debug" +
-          " --enable-sjlj-exceptions" +
-          " --enable-threads=win32" +
-          " --disable-win32-registry"
-          else if crossStageStatic then
-          " --disable-libssp --disable-nls" +
-          " --without-headers" +
-          " --disable-threads " +
-          " --disable-libgomp " +
-          " --disable-libquadmath" +
-          " --disable-shared" +
-          " --disable-libatomic " +  # libatomic requires libc
-          " --disable-decimal-float" # libdecnumber requires libc
-          else
-          (if crossDarwin then " --with-sysroot=${getLib libcCross}/share/sysroot"
-           else                " --with-headers=${getDev libcCross}/include") +
-          " --enable-__cxa_atexit" +
-          " --enable-long-long" +
-          (if crossMingw then
-            " --enable-threads=win32" +
-            " --enable-sjlj-exceptions" +
-            " --enable-hash-synchronization" +
-            " --disable-libssp" +
-            " --disable-nls" +
-            " --with-dwarf2" +
+          [ "--with-headers=${libcCross}/include"
+            "--with-gcc"
+            "--with-gnu-as"
+            "--with-gnu-ld"
+            "--with-gnu-ld"
+            "--disable-shared"
+            "--disable-nls"
+            "--disable-debug"
+            "--enable-sjlj-exceptions"
+            "--enable-threads=win32"
+            "--disable-win32-registry"
+          ] else if crossStageStatic then
+          [ "--disable-libssp --disable-nls"
+            "--without-headers"
+            "--disable-threads "
+            "--disable-libgomp "
+            "--disable-libquadmath"
+            "--disable-shared"
+            "--disable-libatomic "  # libatomic requires libc
+            "--disable-decimal-float" # libdecnumber requires libc
+          ] else
+            (if crossDarwin then ["--with-sysroot=${getLib libcCross}/share/sysroot"]
+             else                ["--with-headers=${getDev libcCross}/include"]) ++
+          [ "--enable-__cxa_atexit"
+            "--enable-long-long"
+          ] ++
+          (if crossMingw then [
+            "--enable-threads=win32"
+            "--enable-sjlj-exceptions"
+            "--enable-hash-synchronization"
+            "--disable-libssp"
+            "--disable-nls"
+            "--with-dwarf2"
             # I think noone uses shared gcc libs in mingw, so we better do the same.
             # In any case, mingw32 g++ linking is broken by default with shared libs,
             # unless adding "-lsupc++" to any linking command. I don't know why.
-            " --disable-shared" +
+            "--disable-shared"
             # To keep ABI compatibility with upstream mingw-w64
-            " --enable-fully-dynamic-string"
-            else (if targetPlatform.libc == "uclibc" then
+            "--enable-fully-dynamic-string"
+          ] else
+            optionals (targetPlatform.libc == "uclibc") [
               # libsanitizer requires netrom/netrom.h which is not
               # available in uclibc.
-              " --disable-libsanitizer" +
+              "--disable-libsanitizer"
               # In uclibc cases, libgomp needs an additional '-ldl'
               # and as I don't know how to pass it, I disable libgomp.
-              " --disable-libgomp" else "") +
-            " --enable-threads=posix" +
-            " --enable-nls" +
-            " --disable-decimal-float") # No final libdecnumber (it may work only in 386)
-          );
+              "--disable-libgomp"
+            ] ++
+            [ "--enable-threads=posix"
+              "--enable-nls"
+              "--disable-decimal-float" # No final libdecnumber (it may work only in 386)
+            ]
+          )
+        );
     stageNameAddon = if crossStageStatic then "-stage-static" else "-stage-final";
     crossNameAddon = if targetPlatform != hostPlatform then "-${targetPlatform.config}" + stageNameAddon else "";
 
-  bootstrap = targetPlatform == hostPlatform;
+    bootstrap = targetPlatform == hostPlatform;
 
 in
 
@@ -340,62 +322,86 @@ stdenv.mkDerivation ({
     then []
     else [ "build" "host" ] ++ stdenv.lib.optional (targetPlatform != hostPlatform) "target";
 
-  configureFlags = "
-    ${if hostPlatform.isSunOS then
-      " --enable-long-long --enable-libssp --enable-threads=posix --disable-nls --enable-__cxa_atexit " +
-      # On Illumos/Solaris GNU as is preferred
-      " --with-gnu-as --without-gnu-ld "
-      else ""}
-    --enable-lto
-    ${if enableMultilib then "--enable-multilib --disable-libquadmath" else "--disable-multilib"}
-    ${if enableShared then "" else "--disable-shared"}
-    ${if enablePlugin then "--enable-plugin" else "--disable-plugin"}
-    ${optionalString (isl != null) "--with-isl=${isl}"}
-    ${if langJava then
-      "--with-ecj-jar=${javaEcj} " +
+  configureFlags =
+    # Basic dependencies
+    [
+      "--with-gmp-include=${gmp.dev}/include"
+      "--with-gmp-lib=${gmp.out}/lib"
+      "--with-mpfr-include=${mpfr.dev}/include"
+      "--with-mpfr-lib=${mpfr.out}/lib"
+      "--with-mpc=${libmpc}"
+    ] ++
+    optional (libelf != null) "--with-libelf=${libelf}" ++
+
+    # Basic configuration
+    [
+      "--enable-lto"
+      "--disable-libstdcxx-pch"
+      "--without-included-gettext"
+      "--with-system-zlib"
+      "--enable-static"
+      "--enable-languages=${
+        concatStrings (intersperse ","
+          (  optional langC        "c"
+          ++ optional langCC       "c++"
+          ++ optional langFortran  "fortran"
+          ++ optional langJava     "java"
+          ++ optional langAda      "ada"
+          ++ optional langVhdl     "vhdl"
+          ++ optional langGo       "go"
+          ++ optional langObjC     "objc"
+          ++ optional langObjCpp   "obj-c++"
+          ++ optionals crossDarwin [ "objc" "obj-c++" ]
+          )
+        )
+      }"
+    ] ++
+
+    # Optional features
+    optional (isl != null) "--with-isl=${isl}" ++
+
+    (if enableMultilib
+      then ["--enable-multilib" "--disable-libquadmath"]
+      else ["--disable-multilib"]) ++
+    optional (!enableShared) "--disable-shared" ++
+    (if enablePlugin
+      then ["--enable-plugin"]
+      else ["--disable-plugin"]) ++
+
+    # Java options
+    optionals langJava [
+      "--with-ecj-jar=${javaEcj} "
 
       # Follow Sun's layout for the convenience of IcedTea/OpenJDK.  See
       # <http://mail.openjdk.java.net/pipermail/distro-pkg-dev/2010-April/008888.html>.
       "--enable-java-home --with-java-home=\${prefix}/lib/jvm/jre "
-      else ""}
-    ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-    ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr}" else ""}
-    --with-gmp-include=${gmp.dev}/include
-    --with-gmp-lib=${gmp.out}/lib
-    --with-mpfr-include=${mpfr.dev}/include
-    --with-mpfr-lib=${mpfr.out}/lib
-    --with-mpc=${libmpc}
-    ${if libelf != null then "--with-libelf=${libelf}" else ""}
-    --disable-libstdcxx-pch
-    --without-included-gettext
-    --with-system-zlib
-    --enable-static
-    --enable-languages=${
-      concatStrings (intersperse ","
-        (  optional langC        "c"
-        ++ optional langCC       "c++"
-        ++ optional langFortran  "fortran"
-        ++ optional langJava     "java"
-        ++ optional langAda      "ada"
-        ++ optional langVhdl     "vhdl"
-        ++ optional langGo       "go"
-        ++ optional langObjC     "objc"
-        ++ optional langObjCpp   "obj-c++"
-        ++ optionals crossDarwin [ "objc" "obj-c++" ]
-        )
-      )
-    }
-    ${if targetPlatform == hostPlatform
-      then if hostPlatform.isDarwin
-        then " --with-native-system-header-dir=${darwin.usr-include}"
-        else " --with-native-system-header-dir=${getDev stdenv.cc.libc}/include"
-      else ""}
-    ${if langAda then " --enable-libada" else ""}
-    ${if targetPlatform == hostPlatform && targetPlatform.isi686 then "--with-arch=i686" else ""}
-    ${if targetPlatform != hostPlatform then crossConfigureFlags else ""}
-    ${if !bootstrap then "--disable-bootstrap" else ""}
-    ${if targetPlatform == hostPlatform then platformFlags else ""}
-  ";
+    ] ++
+    optional javaAwtGtk "--enable-java-awt=gtk" ++
+    optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr}" ++
+
+    # Ada
+    optional langAda "--enable-libada" ++
+
+    # Cross-compilation
+    optional (targetPlatform == hostPlatform) (
+      let incDir = if hostPlatform.isDarwin
+                     then "${darwin.usr-include}"
+                     else "${getDev stdenv.cc.libc}/include";
+      in "--with-native-system-header-dir=${incDir}"
+    ) ++
+
+    optional (targetPlatform == hostPlatform) (mkPlatformFlags stdenv.platform) ++
+    optional (targetPlatform != hostPlatform) crossConfigureFlags ++
+    optional (!bootstrap) "--disable-bootstrap" ++
+
+    # Platform-specific flags
+    optional (targetPlatform == hostPlatform && targetPlatform.isi686) "--with-arch=i686" ++
+    optionals hostPlatform.isSunOS [
+      "--enable-long-long --enable-libssp --enable-threads=posix --disable-nls --enable-__cxa_atexit"
+      # On Illumos/Solaris GNU as is preferred
+      "--with-gnu-as --without-gnu-ld"
+    ]
+  ;
 
   targetConfig = if targetPlatform != hostPlatform then targetPlatform.config else null;
 
@@ -408,17 +414,13 @@ stdenv.mkDerivation ({
     then "install-strip"
     else "install";
 
+  /* For cross-built gcc (build != host == target) */
   crossAttrs = let
     xgccArch = targetPlatform.gcc.arch or null;
     xgccCpu = targetPlatform.gcc.cpu or null;
     xgccAbi = targetPlatform.gcc.abi or null;
     xgccFpu = targetPlatform.gcc.fpu or null;
     xgccFloat = targetPlatform.gcc.float or null;
-    xwithArch = if xgccArch != null then " --with-arch=${xgccArch}" else "";
-    xwithCpu = if xgccCpu != null then " --with-cpu=${xgccCpu}" else "";
-    xwithAbi = if xgccAbi != null then " --with-abi=${xgccAbi}" else "";
-    xwithFpu = if xgccFpu != null then " --with-fpu=${xgccFpu}" else "";
-    xwithFloat = if xgccFloat != null then " --with-float=${xgccFloat}" else "";
   in {
     AR = "${targetPlatform.config}-ar";
     LD = "${targetPlatform.config}-ld";
@@ -432,37 +434,39 @@ stdenv.mkDerivation ({
     # If we are making a cross compiler, cross != null
     NIX_CC_CROSS = optionalString (targetPlatform == hostPlatform) builtins.toString stdenv.cc;
     dontStrip = true;
-    configureFlags = ''
-      ${if enableMultilib then "" else "--disable-multilib"}
-      ${if enableShared then "" else "--disable-shared"}
-      ${if langJava then "--with-ecj-jar=${javaEcj.crossDrv}" else ""}
-      ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-      ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr.crossDrv}" else ""}
-      --with-gmp=${gmp.crossDrv}
-      --with-mpfr=${mpfr.crossDrv}
-      --with-mpc=${libmpc.crossDrv}
-      --disable-libstdcxx-pch
-      --without-included-gettext
-      --with-system-zlib
-      --enable-languages=${
-        concatStrings (intersperse ","
-          (  optional langC        "c"
-          ++ optional langCC       "c++"
-          ++ optional langFortran  "fortran"
-          ++ optional langJava     "java"
-          ++ optional langAda      "ada"
-          ++ optional langVhdl     "vhdl"
-          ++ optional langGo       "go"
+    configureFlags =
+      optional (!enableMultilib) "--disable-multilib" ++
+      optional (!enableShared) "--disable-shared" ++
+      optional langJava "--with-ecj-jar=${javaEcj.crossDrv}" ++
+      optional javaAwtGtk "--enable-java-awt=gtk" ++
+      optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr.crossDrv}" ++
+      [
+        "--with-gmp=${gmp.crossDrv}"
+        "--with-mpfr=${mpfr.crossDrv}"
+        "--with-mpc=${libmpc.crossDrv}"
+        "--disable-libstdcxx-pch"
+        "--without-included-gettext"
+        "--with-system-zlib"
+        "--enable-languages=${
+          concatStrings (intersperse ","
+            (  optional langC        "c"
+            ++ optional langCC       "c++"
+            ++ optional langFortran  "fortran"
+            ++ optional langJava     "java"
+            ++ optional langAda      "ada"
+            ++ optional langVhdl     "vhdl"
+            ++ optional langGo       "go"
+            )
           )
-        )
-      }
-      ${if langAda then " --enable-libada" else ""}
-      ${xwithArch}
-      ${xwithCpu}
-      ${xwithAbi}
-      ${xwithFpu}
-      ${xwithFloat}
-    '';
+        }"
+      ] ++
+      optional langAda "--enable-libada" ++
+      optional (xgccArch != null) "--with-arch=${xgccArch}" ++
+      optional (xgccCpu != null) "--with-cpu=${xgccCpu}" ++
+      optional (xgccAbi != null) "--with-abi=${xgccAbi}" ++
+      optional (xgccFpu != null) "--with-fpu=${xgccFpu}" ++
+      optional (xgccFloat != null) "--with-float=${xgccFloat}"
+    ;
     buildFlags = "";
   };
 
diff --git a/pkgs/development/compilers/gcc/6/default.nix b/pkgs/development/compilers/gcc/6/default.nix
index 03c6b3834ea..f0d2ab6a914 100644
--- a/pkgs/development/compilers/gcc/6/default.nix
+++ b/pkgs/development/compilers/gcc/6/default.nix
@@ -100,103 +100,86 @@ let version = "6.4.0";
     javaAwtGtk = langJava && x11Support;
 
     /* Platform flags */
-    platformFlags = let
-        gccArch = stdenv.platform.gcc.arch or null;
-        gccCpu = stdenv.platform.gcc.cpu or null;
-        gccAbi = stdenv.platform.gcc.abi or null;
-        gccFpu = stdenv.platform.gcc.fpu or null;
-        gccFloat = stdenv.platform.gcc.float or null;
-        gccMode = stdenv.platform.gcc.mode or null;
-        withArch = if gccArch != null then " --with-arch=${gccArch}" else "";
-        withCpu = if gccCpu != null then " --with-cpu=${gccCpu}" else "";
-        withAbi = if gccAbi != null then " --with-abi=${gccAbi}" else "";
-        withFpu = if gccFpu != null then " --with-fpu=${gccFpu}" else "";
-        withFloat = if gccFloat != null then " --with-float=${gccFloat}" else "";
-        withMode = if gccMode != null then " --with-mode=${gccMode}" else "";
+    mkPlatformFlags = platform: let
+        gccArch = platform.gcc.arch or null;
+        gccCpu = platform.gcc.cpu or null;
+        gccAbi = platform.gcc.abi or null;
+        gccFpu = platform.gcc.fpu or null;
+        gccFloat = platform.gcc.float or null;
+        gccMode = platform.gcc.mode or null;
       in
-        withArch +
-        withCpu +
-        withAbi +
-        withFpu +
-        withFloat +
-        withMode;
-
-    /* Cross-gcc settings */
+        optional (gccArch != null) "--with-arch=${gccArch}" ++
+        optional (gccCpu != null) "--with-cpu=${gccCpu}" ++
+        optional (gccAbi != null) "--with-abi=${gccAbi}" ++
+        optional (gccFpu != null) "--with-fpu=${gccFpu}" ++
+        optional (gccFloat != null) "--with-float=${gccFloat}" ++
+        optional (gccMode != null) "--with-mode=${gccMode}";
+
+    /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
     crossDarwin = targetPlatform != hostPlatform && targetPlatform.libc == "libSystem";
-    crossConfigureFlags = let
-        gccArch = targetPlatform.gcc.arch or null;
-        gccCpu = targetPlatform.gcc.cpu or null;
-        gccAbi = targetPlatform.gcc.abi or null;
-        gccFpu = targetPlatform.gcc.fpu or null;
-        gccFloat = targetPlatform.gcc.float or null;
-        gccMode = targetPlatform.gcc.mode or null;
-        withArch = if gccArch != null then " --with-arch=${gccArch}" else "";
-        withCpu = if gccCpu != null then " --with-cpu=${gccCpu}" else "";
-        withAbi = if gccAbi != null then " --with-abi=${gccAbi}" else "";
-        withFpu = if gccFpu != null then " --with-fpu=${gccFpu}" else "";
-        withFloat = if gccFloat != null then " --with-float=${gccFloat}" else "";
-        withMode = if gccMode != null then " --with-mode=${gccMode}" else "";
-      in
-        withArch +
-        withCpu +
-        withAbi +
-        withFpu +
-        withFloat +
-        withMode +
+    crossConfigureFlags =
+        mkPlatformFlags targetPlatform ++
+
         # Ensure that -print-prog-name is able to find the correct programs.
-        " --with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as" +
-        " --with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" +
+        [ " --with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as"
+          " --with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" ] ++
         (if crossMingw && crossStageStatic then
-          " --with-headers=${libcCross}/include" +
-          " --with-gcc" +
-          " --with-gnu-as" +
-          " --with-gnu-ld" +
-          " --with-gnu-ld" +
-          " --disable-shared" +
-          " --disable-nls" +
-          " --disable-debug" +
-          " --enable-sjlj-exceptions" +
-          " --enable-threads=win32" +
-          " --disable-win32-registry"
-          else if crossStageStatic then
-          " --disable-libssp --disable-nls" +
-          " --without-headers" +
-          " --disable-threads " +
-          " --disable-libgomp " +
-          " --disable-libquadmath" +
-          " --disable-shared" +
-          " --disable-libatomic " +  # libatomic requires libc
-          " --disable-decimal-float" # libdecnumber requires libc
-          else
-          (if crossDarwin then " --with-sysroot=${getLib libcCross}/share/sysroot"
-           else                " --with-headers=${getDev libcCross}/include") +
-          " --enable-__cxa_atexit" +
-          " --enable-long-long" +
-          (if crossMingw then
-            " --enable-threads=win32" +
-            " --enable-sjlj-exceptions" +
-            " --enable-hash-synchronization" +
-            " --disable-libssp" +
-            " --disable-nls" +
-            " --with-dwarf2" +
+          [ "--with-headers=${libcCross}/include"
+            "--with-gcc"
+            "--with-gnu-as"
+            "--with-gnu-ld"
+            "--with-gnu-ld"
+            "--disable-shared"
+            "--disable-nls"
+            "--disable-debug"
+            "--enable-sjlj-exceptions"
+            "--enable-threads=win32"
+            "--disable-win32-registry"
+        ] else if crossStageStatic then [
+            "--disable-libssp"
+            "--disable-nls"
+            "--without-headers"
+            "--disable-threads"
+            "--disable-libgomp"
+            "--disable-libquadmath"
+            "--disable-shared"
+            "--disable-libatomic"  # libatomic requires libc
+            "--disable-decimal-float" # libdecnumber requires libc
+        ] else
+          (if crossDarwin then ["--with-sysroot=${getLib libcCross}/share/sysroot"]
+           else                ["--with-headers=${getDev libcCross}/include"]) ++
+
+          [ "--enable-__cxa_atexit"
+            "--enable-long-long"
+          ] ++
+
+          (if crossMingw then [
+            "--enable-threads=win32"
+            "--enable-sjlj-exceptions"
+            "--enable-hash-synchronization"
+            "--disable-libssp"
+            "--disable-nls"
+            "--with-dwarf2"
             # I think noone uses shared gcc libs in mingw, so we better do the same.
             # In any case, mingw32 g++ linking is broken by default with shared libs,
             # unless adding "-lsupc++" to any linking command. I don't know why.
-            " --disable-shared" +
+            "--disable-shared"
             # To keep ABI compatibility with upstream mingw-w64
-            " --enable-fully-dynamic-string"
-            else (if targetPlatform.libc == "uclibc" then
-              # libsanitizer requires netrom/netrom.h which is not
-              # available in uclibc.
-              " --disable-libsanitizer" +
-              # In uclibc cases, libgomp needs an additional '-ldl'
-              # and as I don't know how to pass it, I disable libgomp.
-              " --disable-libgomp" else "") +
-            " --enable-threads=posix" +
-            " --enable-nls" +
-            " --disable-decimal-float") # No final libdecnumber (it may work only in 386)
-          );
+            "--enable-fully-dynamic-string"
+            ] else
+              optionals (targetPlatform.libc == "uclibc") [
+                # libsanitizer requires netrom/netrom.h which is not
+                # available in uclibc.
+                "--disable-libsanitizer"
+                # In uclibc cases, libgomp needs an additional '-ldl'
+                # and as I don't know how to pass it, I disable libgomp.
+                "--disable-libgomp" ] ++
+              [ "--enable-threads=posix"
+                "--enable-nls"
+                "--disable-decimal-float" # No final libdecnumber (it may work only in 386)
+              ])
+        );
     stageNameAddon = if crossStageStatic then "-stage-static" else "-stage-final";
     crossNameAddon = if targetPlatform != hostPlatform then "-${targetPlatform.config}" + stageNameAddon else "";
 
@@ -341,85 +324,104 @@ stdenv.mkDerivation ({
     then []
     else [ "build" "host" ] ++ stdenv.lib.optional (targetPlatform != hostPlatform) "target";
 
-  configureFlags = "
-    ${if hostPlatform.isSunOS then
-      " --enable-long-long --enable-libssp --enable-threads=posix --disable-nls --enable-__cxa_atexit " +
-      # On Illumos/Solaris GNU as is preferred
-      " --with-gnu-as --without-gnu-ld "
-      else ""}
-    --enable-lto
-    ${if enableMultilib then "--enable-multilib --disable-libquadmath" else "--disable-multilib"}
-    ${if enableShared then "" else "--disable-shared"}
-    ${if enablePlugin then "--enable-plugin" else "--disable-plugin"}
-    ${optionalString (isl != null) "--with-isl=${isl}"}
-    ${if langJava then
-      "--with-ecj-jar=${javaEcj} " +
+  configureFlags =
+    # Basic dependencies
+    [
+      "--with-gmp-include=${gmp.dev}/include"
+      "--with-gmp-lib=${gmp.out}/lib"
+      "--with-mpfr-include=${mpfr.dev}/include"
+      "--with-mpfr-lib=${mpfr.out}/lib"
+      "--with-mpc=${libmpc}"
+    ] ++
+    optional (libelf != null) "--with-libelf=${libelf}" ++
+
+    # Basic configuration
+    [
+      "--enable-lto"
+      "--disable-libstdcxx-pch"
+      "--without-included-gettext"
+      "--with-system-zlib"
+      "--enable-static"
+      "--enable-languages=${
+        concatStrings (intersperse ","
+          (  optional langC        "c"
+          ++ optional langCC       "c++"
+          ++ optional langFortran  "fortran"
+          ++ optional langJava     "java"
+          ++ optional langAda      "ada"
+          ++ optional langVhdl     "vhdl"
+          ++ optional langGo       "go"
+          ++ optional langObjC     "objc"
+          ++ optional langObjCpp   "obj-c++"
+          ++ optionals crossDarwin [ "objc" "obj-c++" ]
+          )
+        )
+      }"
+    ] ++
+
+    (if enableMultilib
+      then ["--enable-multilib" "--disable-libquadmath"]
+      else ["--disable-multilib"]) ++
+    optional (!enableShared) "--disable-shared" ++
+    (if enablePlugin
+      then ["--enable-plugin"]
+      else ["--disable-plugin"]) ++
+
+    # Optional features
+    optional (isl != null) "--with-isl=${isl}" ++
+
+    # Java options
+    optionals langJava [
+      "--with-ecj-jar=${javaEcj} "
 
       # Follow Sun's layout for the convenience of IcedTea/OpenJDK.  See
       # <http://mail.openjdk.java.net/pipermail/distro-pkg-dev/2010-April/008888.html>.
-      "--enable-java-home --with-java-home=\${prefix}/lib/jvm/jre "
-      else ""}
-    ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-    ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr}" else ""}
-    --with-gmp-include=${gmp.dev}/include
-    --with-gmp-lib=${gmp.out}/lib
-    --with-mpfr-include=${mpfr.dev}/include
-    --with-mpfr-lib=${mpfr.out}/lib
-    --with-mpc=${libmpc}
-    ${if libelf != null then "--with-libelf=${libelf}" else ""}
-    --disable-libstdcxx-pch
-    --without-included-gettext
-    --with-system-zlib
-    --enable-static
-    --enable-languages=${
-      concatStrings (intersperse ","
-        (  optional langC        "c"
-        ++ optional langCC       "c++"
-        ++ optional langFortran  "fortran"
-        ++ optional langJava     "java"
-        ++ optional langAda      "ada"
-        ++ optional langVhdl     "vhdl"
-        ++ optional langGo       "go"
-        ++ optional langObjC     "objc"
-        ++ optional langObjCpp   "obj-c++"
-        ++ optionals crossDarwin [ "objc" "obj-c++" ]
-        )
-      )
-    }
-    ${if targetPlatform == hostPlatform
-      then if hostPlatform.isDarwin
-        then " --with-native-system-header-dir=${darwin.usr-include}"
-        else " --with-native-system-header-dir=${getDev stdenv.cc.libc}/include"
-      else ""}
-    ${if langAda then " --enable-libada" else ""}
-    ${if targetPlatform == hostPlatform && targetPlatform.isi686 then "--with-arch=i686" else ""}
-    ${if targetPlatform != hostPlatform then crossConfigureFlags else ""}
-    ${if !bootstrap then "--disable-bootstrap" else ""}
-    ${if targetPlatform == hostPlatform then platformFlags else ""}
-  ";
+      "--enable-java-home"
+      "--with-java-home=\${prefix}/lib/jvm/jre"
+    ] ++
+    optional javaAwtGtk "--enable-java-awt=gtk" ++
+    optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr}" ++
+
+    # Ada
+    optional langAda "--enable-libada" ++
+
+    # Cross compilation
+    optional (targetPlatform == hostPlatform) (
+      let incDir = if hostPlatform.isDarwin
+                     then "${darwin.usr-include}"
+                     else "${getDev stdenv.cc.libc}/include";
+      in "--with-native-system-header-dir=${incDir}"
+    ) ++
+
+    optional (targetPlatform != hostPlatform) crossConfigureFlags ++
+    optional (!bootstrap) "--disable-bootstrap" ++
+
+    # Platform-specific flags
+    optional (targetPlatform == hostPlatform && targetPlatform.isi686) "--with-arch=i686" ++
+    optionals (hostPlatform.isSunOS) [
+      " --enable-long-long --enable-libssp --enable-threads=posix --disable-nls --enable-__cxa_atexit"
+      # On Illumos/Solaris GNU as is preferred
+      " --with-gnu-as --without-gnu-ld"
+    ]
+  ;
 
   targetConfig = if targetPlatform != hostPlatform then targetPlatform.config else null;
 
-  buildFlags = if bootstrap then
-    (if profiledCompiler then "profiledbootstrap" else "bootstrap")
-    else "";
+  buildFlags =
+    optional bootstrap (if profiledCompiler then "profiledbootstrap" else "bootstrap");
 
   installTargets =
     if stripped
     then "install-strip"
     else "install";
 
+  /* For cross-built gcc (build != host == target) */
   crossAttrs = let
     xgccArch = targetPlatform.gcc.arch or null;
     xgccCpu = targetPlatform.gcc.cpu or null;
     xgccAbi = targetPlatform.gcc.abi or null;
     xgccFpu = targetPlatform.gcc.fpu or null;
     xgccFloat = targetPlatform.gcc.float or null;
-    xwithArch = if xgccArch != null then " --with-arch=${xgccArch}" else "";
-    xwithCpu = if xgccCpu != null then " --with-cpu=${xgccCpu}" else "";
-    xwithAbi = if xgccAbi != null then " --with-abi=${xgccAbi}" else "";
-    xwithFpu = if xgccFpu != null then " --with-fpu=${xgccFpu}" else "";
-    xwithFloat = if xgccFloat != null then " --with-float=${xgccFloat}" else "";
   in {
     AR = "${targetPlatform.config}-ar";
     LD = "${targetPlatform.config}-ld";
@@ -433,37 +435,39 @@ stdenv.mkDerivation ({
     # If we are making a cross compiler, cross != null
     NIX_CC_CROSS = optionalString (targetPlatform == hostPlatform) builtins.toString stdenv.cc;
     dontStrip = true;
-    configureFlags = ''
-      ${if enableMultilib then "" else "--disable-multilib"}
-      ${if enableShared then "" else "--disable-shared"}
-      ${if langJava then "--with-ecj-jar=${javaEcj.crossDrv}" else ""}
-      ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-      ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr.crossDrv}" else ""}
-      --with-gmp=${gmp.crossDrv}
-      --with-mpfr=${mpfr.crossDrv}
-      --with-mpc=${libmpc.crossDrv}
-      --disable-libstdcxx-pch
-      --without-included-gettext
-      --with-system-zlib
-      --enable-languages=${
-        concatStrings (intersperse ","
-          (  optional langC        "c"
-          ++ optional langCC       "c++"
-          ++ optional langFortran  "fortran"
-          ++ optional langJava     "java"
-          ++ optional langAda      "ada"
-          ++ optional langVhdl     "vhdl"
-          ++ optional langGo       "go"
+    configureFlags =
+      optional (!enableMultilib) "--disable-multilib" ++
+      optional (!enableShared) "--disable-shared" ++
+      optional langJava "--with-ecj-jar=${javaEcj.crossDrv}" ++
+      optional javaAwtGtk "--enable-java-awt=gtk" ++
+      optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr.crossDrv}" ++
+      [
+        "--with-gmp=${gmp.crossDrv}"
+        "--with-mpfr=${mpfr.crossDrv}"
+        "--with-mpc=${libmpc.crossDrv}"
+        "--disable-libstdcxx-pch"
+        "--without-included-gettext"
+        "--with-system-zlib"
+        "--enable-languages=${
+          concatStrings (intersperse ","
+            (  optional langC        "c"
+            ++ optional langCC       "c++"
+            ++ optional langFortran  "fortran"
+            ++ optional langJava     "java"
+            ++ optional langAda      "ada"
+            ++ optional langVhdl     "vhdl"
+            ++ optional langGo       "go"
+            )
           )
-        )
-      }
-      ${if langAda then " --enable-libada" else ""}
-      ${xwithArch}
-      ${xwithCpu}
-      ${xwithAbi}
-      ${xwithFpu}
-      ${xwithFloat}
-    '';
+        }"
+      ] ++
+      optional langAda "--enable-libada" ++
+      optional (xgccArch != null) "--with-arch=${xgccArch}" ++
+      optional (xgccCpu != null) "--with-cpu=${xgccCpu}" ++
+      optional (xgccAbi != null) "--with-abi=${xgccAbi}" ++
+      optional (xgccFpu != null) "--with-fpu=${xgccFpu}" ++
+      optional (xgccFloat != null) "--with-float=${xgccFloat}"
+    ;
     buildFlags = "";
   };
 
diff --git a/pkgs/development/compilers/gcc/7/default.nix b/pkgs/development/compilers/gcc/7/default.nix
index 3a7c0eb6443..e44b32ef9d3 100644
--- a/pkgs/development/compilers/gcc/7/default.nix
+++ b/pkgs/development/compilers/gcc/7/default.nix
@@ -98,108 +98,90 @@ let version = "7.2.0";
     javaAwtGtk = langJava && x11Support;
 
     /* Platform flags */
-    platformFlags = let
-        gccArch = stdenv.platform.gcc.arch or null;
-        gccCpu = stdenv.platform.gcc.cpu or null;
-        gccAbi = stdenv.platform.gcc.abi or null;
-        gccFpu = stdenv.platform.gcc.fpu or null;
-        gccFloat = stdenv.platform.gcc.float or null;
-        gccMode = stdenv.platform.gcc.mode or null;
-        withArch = if gccArch != null then " --with-arch=${gccArch}" else "";
-        withCpu = if gccCpu != null then " --with-cpu=${gccCpu}" else "";
-        withAbi = if gccAbi != null then " --with-abi=${gccAbi}" else "";
-        withFpu = if gccFpu != null then " --with-fpu=${gccFpu}" else "";
-        withFloat = if gccFloat != null then " --with-float=${gccFloat}" else "";
-        withMode = if gccMode != null then " --with-mode=${gccMode}" else "";
-      in
-        withArch +
-        withCpu +
-        withAbi +
-        withFpu +
-        withFloat +
-        withMode;
-
-    /* Cross-gcc settings */
+    mkPlatformFlags = platform: let
+        gccArch = platform.gcc.arch or null;
+        gccCpu = platform.gcc.cpu or null;
+        gccAbi = platform.gcc.abi or null;
+        gccFpu = platform.gcc.fpu or null;
+        gccFloat = platform.gcc.float or null;
+        gccMode = platform.gcc.mode or null;
+     in
+        optional (gccArch != null) "--with-arch=${gccArch}" ++
+        optional (gccCpu != null) "--with-cpu=${gccCpu}" ++
+        optional (gccAbi != null) "--with-abi=${gccAbi}" ++
+        optional (gccFpu != null) "--with-fpu=${gccFpu}" ++
+        optional (gccFloat != null) "--with-float=${gccFloat}" ++
+        optional (gccMode != null) "--with-mode=${gccMode}";
+
+    /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
     crossDarwin = targetPlatform != hostPlatform && targetPlatform.libc == "libSystem";
-    crossConfigureFlags = let
-        gccArch = targetPlatform.gcc.arch or null;
-        gccCpu = targetPlatform.gcc.cpu or null;
-        gccAbi = targetPlatform.gcc.abi or null;
-        gccFpu = targetPlatform.gcc.fpu or null;
-        gccFloat = targetPlatform.gcc.float or null;
-        gccMode = targetPlatform.gcc.mode or null;
-        withArch = if gccArch != null then " --with-arch=${gccArch}" else "";
-        withCpu = if gccCpu != null then " --with-cpu=${gccCpu}" else "";
-        withAbi = if gccAbi != null then " --with-abi=${gccAbi}" else "";
-        withFpu = if gccFpu != null then " --with-fpu=${gccFpu}" else "";
-        withFloat = if gccFloat != null then " --with-float=${gccFloat}" else "";
-        withMode = if gccMode != null then " --with-mode=${gccMode}" else "";
-      in
-        withArch +
-        withCpu +
-        withAbi +
-        withFpu +
-        withFloat +
-        withMode +
+    crossConfigureFlags =
+        mkPlatformFlags targetPlatform ++
+
         # Ensure that -print-prog-name is able to find the correct programs.
-        " --with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as" +
-        " --with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" +
+        [ "--with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as"
+          "--with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" ] ++
         (if crossMingw && crossStageStatic then
-          " --with-headers=${libcCross}/include" +
-          " --with-gcc" +
-          " --with-gnu-as" +
-          " --with-gnu-ld" +
-          " --with-gnu-ld" +
-          " --disable-shared" +
-          " --disable-nls" +
-          " --disable-debug" +
-          " --enable-sjlj-exceptions" +
-          " --enable-threads=win32" +
-          " --disable-win32-registry"
-          else if crossStageStatic then
-          " --disable-libssp --disable-nls" +
-          " --without-headers" +
-          " --disable-threads " +
-          " --disable-libgomp " +
-          " --disable-libquadmath" +
-          " --disable-shared" +
-          " --disable-libatomic " +  # libatomic requires libc
-          " --disable-decimal-float" # libdecnumber requires libc
-          else
-          (if crossDarwin then " --with-sysroot=${getLib libcCross}/share/sysroot"
-           else                " --with-headers=${getDev libcCross}/include") +
-          # Ensure that -print-prog-name is able to find the correct programs.
-          " --enable-__cxa_atexit" +
-          " --enable-long-long" +
-          (if crossMingw then
-            " --enable-threads=win32" +
-            " --enable-sjlj-exceptions" +
-            " --enable-hash-synchronization" +
-            " --disable-libssp" +
-            " --disable-nls" +
-            " --with-dwarf2" +
+          [ "--with-headers=${libcCross}/include"
+            "--with-gcc"
+            "--with-gnu-as"
+            "--with-gnu-ld"
+            "--with-gnu-ld"
+            "--disable-shared"
+            "--disable-nls"
+            "--disable-debug"
+            "--enable-sjlj-exceptions"
+            "--enable-threads=win32"
+            "--disable-win32-registry"
+          ] else if crossStageStatic then
+          [ "--disable-libssp"
+            "--disable-nls"
+            "--without-headers"
+            "--disable-threads "
+            "--disable-libgomp "
+            "--disable-libquadmath"
+            "--disable-shared"
+            "--disable-libatomic "  # libatomic requires libc
+            "--disable-decimal-float" # libdecnumber requires libc
+          ] else
+            (if crossDarwin then ["--with-sysroot=${getLib libcCross}/share/sysroot"]
+             else                ["--with-headers=${getDev libcCross}/include"]) ++
+          [ "--enable-__cxa_atexit"
+            "--enable-long-long"
+          ] ++
+
+          (if crossMingw then [
+            "--enable-threads=win32"
+            "--enable-sjlj-exceptions"
+            "--enable-hash-synchronization"
+            "--disable-libssp"
+            "--disable-nls"
+            "--with-dwarf2"
             # I think noone uses shared gcc libs in mingw, so we better do the same.
             # In any case, mingw32 g++ linking is broken by default with shared libs,
             # unless adding "-lsupc++" to any linking command. I don't know why.
-            " --disable-shared" +
+            "--disable-shared"
             # To keep ABI compatibility with upstream mingw-w64
-            " --enable-fully-dynamic-string"
-            else (if targetPlatform.libc == "uclibc" then
+            "--enable-fully-dynamic-string"
+          ] else
+            optionals (targetPlatform.libc == "uclibc") [
               # libsanitizer requires netrom/netrom.h which is not
               # available in uclibc.
-              " --disable-libsanitizer" +
+              "--disable-libsanitizer"
               # In uclibc cases, libgomp needs an additional '-ldl'
               # and as I don't know how to pass it, I disable libgomp.
-              " --disable-libgomp" else "") +
-            " --enable-threads=posix" +
-            " --enable-nls" +
-            " --disable-decimal-float") # No final libdecnumber (it may work only in 386)
+              "--disable-libgomp"
+            ] ++
+            [ "--enable-threads=posix"
+              "--enable-nls"
+              "--disable-decimal-float" # No final libdecnumber (it may work only in 386)
+            ])
           );
     stageNameAddon = if crossStageStatic then "-stage-static" else "-stage-final";
     crossNameAddon = if targetPlatform != hostPlatform then "-${targetPlatform.config}" + stageNameAddon else "";
 
-  bootstrap = targetPlatform == hostPlatform;
+    bootstrap = targetPlatform == hostPlatform;
 
 in
 
@@ -335,62 +317,86 @@ stdenv.mkDerivation ({
     then []
     else [ "build" "host" ] ++ stdenv.lib.optional (targetPlatform != hostPlatform) "target";
 
-  configureFlags = "
-    ${if hostPlatform.isSunOS then
-      " --enable-long-long --enable-libssp --enable-threads=posix --disable-nls --enable-__cxa_atexit " +
-      # On Illumos/Solaris GNU as is preferred
-      " --with-gnu-as --without-gnu-ld "
-      else ""}
-    --enable-lto
-    ${if enableMultilib then "--enable-multilib --disable-libquadmath" else "--disable-multilib"}
-    ${if enableShared then "" else "--disable-shared"}
-    ${if enablePlugin then "--enable-plugin" else "--disable-plugin"}
-    ${optionalString (isl != null) "--with-isl=${isl}"}
-    ${if langJava then
-      "--with-ecj-jar=${javaEcj} " +
+  configureFlags =
+    # Basic dependencies
+    [
+      "--with-gmp-include=${gmp.dev}/include"
+      "--with-gmp-lib=${gmp.out}/lib"
+      "--with-mpfr-include=${mpfr.dev}/include"
+      "--with-mpfr-lib=${mpfr.out}/lib"
+      "--with-mpc=${libmpc}"
+    ] ++
+    optional (libelf != null) "--with-libelf=${libelf}" ++
+
+    # Basic configuration
+    [
+      "--enable-lto"
+      "--disable-libstdcxx-pch"
+      "--without-included-gettext"
+      "--with-system-zlib"
+      "--enable-static"
+      "--enable-languages=${
+        concatStrings (intersperse ","
+          (  optional langC        "c"
+          ++ optional langCC       "c++"
+          ++ optional langFortran  "fortran"
+          ++ optional langJava     "java"
+          ++ optional langAda      "ada"
+          ++ optional langVhdl     "vhdl"
+          ++ optional langGo       "go"
+          ++ optional langObjC     "objc"
+          ++ optional langObjCpp   "obj-c++"
+          ++ optionals crossDarwin [ "objc" "obj-c++" ]
+          )
+        )
+      }"
+    ] ++
+
+    (if enableMultilib
+      then ["--enable-multilib" "--disable-libquadmath"]
+      else ["--disable-multilib"]) ++
+    optional (!enableShared) "--disable-shared" ++
+    (if enablePlugin
+      then ["--enable-plugin"]
+      else ["--disable-plugin"]) ++
+
+    # Optional features
+    optional (isl != null) "--with-isl=${isl}" ++
+
+    # Java options
+    optionals langJava [
+      "--with-ecj-jar=${javaEcj} "
 
       # Follow Sun's layout for the convenience of IcedTea/OpenJDK.  See
       # <http://mail.openjdk.java.net/pipermail/distro-pkg-dev/2010-April/008888.html>.
       "--enable-java-home --with-java-home=\${prefix}/lib/jvm/jre "
-      else ""}
-    ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-    ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr}" else ""}
-    --with-gmp-include=${gmp.dev}/include
-    --with-gmp-lib=${gmp.out}/lib
-    --with-mpfr-include=${mpfr.dev}/include
-    --with-mpfr-lib=${mpfr.out}/lib
-    --with-mpc=${libmpc}
-    ${if libelf != null then "--with-libelf=${libelf}" else ""}
-    --disable-libstdcxx-pch
-    --without-included-gettext
-    --with-system-zlib
-    --enable-static
-    --enable-languages=${
-      concatStrings (intersperse ","
-        (  optional langC        "c"
-        ++ optional langCC       "c++"
-        ++ optional langFortran  "fortran"
-        ++ optional langJava     "java"
-        ++ optional langAda      "ada"
-        ++ optional langVhdl     "vhdl"
-        ++ optional langGo       "go"
-        ++ optional langObjC     "objc"
-        ++ optional langObjCpp   "obj-c++"
-        ++ optionals crossDarwin [ "objc" "obj-c++" ]
-        )
-      )
-    }
-    ${if targetPlatform == hostPlatform
-      then if hostPlatform.isDarwin
-        then " --with-native-system-header-dir=${darwin.usr-include}"
-        else " --with-native-system-header-dir=${getDev stdenv.cc.libc}/include"
-      else ""}
-    ${if langAda then " --enable-libada" else ""}
-    ${if targetPlatform == hostPlatform && targetPlatform.isi686 then "--with-arch=i686" else ""}
-    ${if targetPlatform != hostPlatform then crossConfigureFlags else ""}
-    ${if !bootstrap then "--disable-bootstrap" else ""}
-    ${if targetPlatform == hostPlatform then platformFlags else ""}
-  ";
+    ] ++
+    optional javaAwtGtk "--enable-java-awt=gtk" ++
+    optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr}" ++
+
+    # Ada
+    optional langAda "--enable-libada" ++
+
+    # Cross-compilation
+    optional (targetPlatform == hostPlatform) (
+      let incDir = if hostPlatform.isDarwin
+                     then "${darwin.usr-include}"
+                     else "${getDev stdenv.cc.libc}/include";
+      in "--with-native-system-header-dir=${incDir}"
+    ) ++
+
+    optional (targetPlatform == hostPlatform) (mkPlatformFlags stdenv.platform) ++
+    optional (targetPlatform != hostPlatform) crossConfigureFlags ++
+    optional (!bootstrap) "--disable-bootstrap" ++
+
+    # Platform-specific flags
+    optional (targetPlatform == hostPlatform && targetPlatform.isi686) "--with-arch=i686" ++
+    optionals hostPlatform.isSunOS [
+      "--enable-long-long --enable-libssp --enable-threads=posix --disable-nls --enable-__cxa_atexit"
+      # On Illumos/Solaris GNU as is preferred
+      "--with-gnu-as --without-gnu-ld"
+    ]
+  ;
 
   targetConfig = if targetPlatform != hostPlatform then targetPlatform.config else null;
 
@@ -403,17 +409,13 @@ stdenv.mkDerivation ({
     then "install-strip"
     else "install";
 
+  /* For cross-built gcc (build != host == target) */
   crossAttrs = let
     xgccArch = targetPlatform.gcc.arch or null;
     xgccCpu = targetPlatform.gcc.cpu or null;
     xgccAbi = targetPlatform.gcc.abi or null;
     xgccFpu = targetPlatform.gcc.fpu or null;
     xgccFloat = targetPlatform.gcc.float or null;
-    xwithArch = if xgccArch != null then " --with-arch=${xgccArch}" else "";
-    xwithCpu = if xgccCpu != null then " --with-cpu=${xgccCpu}" else "";
-    xwithAbi = if xgccAbi != null then " --with-abi=${xgccAbi}" else "";
-    xwithFpu = if xgccFpu != null then " --with-fpu=${xgccFpu}" else "";
-    xwithFloat = if xgccFloat != null then " --with-float=${xgccFloat}" else "";
   in {
     AR = "${targetPlatform.config}-ar";
     LD = "${targetPlatform.config}-ld";
@@ -427,37 +429,39 @@ stdenv.mkDerivation ({
     # If we are making a cross compiler, targetPlatform != hostPlatform
     NIX_CC_CROSS = if targetPlatform == hostPlatform then "${stdenv.ccCross}" else "";
     dontStrip = true;
-    configureFlags = ''
-      ${if enableMultilib then "" else "--disable-multilib"}
-      ${if enableShared then "" else "--disable-shared"}
-      ${if langJava then "--with-ecj-jar=${javaEcj.crossDrv}" else ""}
-      ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-      ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr.crossDrv}" else ""}
-      --with-gmp=${gmp.crossDrv}
-      --with-mpfr=${mpfr.crossDrv}
-      --with-mpc=${libmpc.crossDrv}
-      --disable-libstdcxx-pch
-      --without-included-gettext
-      --with-system-zlib
-      --enable-languages=${
-        concatStrings (intersperse ","
-          (  optional langC        "c"
-          ++ optional langCC       "c++"
-          ++ optional langFortran  "fortran"
-          ++ optional langJava     "java"
-          ++ optional langAda      "ada"
-          ++ optional langVhdl     "vhdl"
-          ++ optional langGo       "go"
+    configureFlags =
+      optional (!enableMultilib) "--disable-multilib" ++
+      optional (!enableShared) "--disable-shared" ++
+      optional langJava "--with-ecj-jar=${javaEcj.crossDrv}" ++
+      optional javaAwtGtk "--enable-java-awt=gtk" ++
+      optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr.crossDrv}" ++
+      [
+        "--with-gmp=${gmp.crossDrv}"
+        "--with-mpfr=${mpfr.crossDrv}"
+        "--with-mpc=${libmpc.crossDrv}"
+        "--disable-libstdcxx-pch"
+        "--without-included-gettext"
+        "--with-system-zlib"
+        "--enable-languages=${
+          concatStrings (intersperse ","
+            (  optional langC        "c"
+            ++ optional langCC       "c++"
+            ++ optional langFortran  "fortran"
+            ++ optional langJava     "java"
+            ++ optional langAda      "ada"
+            ++ optional langVhdl     "vhdl"
+            ++ optional langGo       "go"
+            )
           )
-        )
-      }
-      ${if langAda then " --enable-libada" else ""}
-      ${xwithArch}
-      ${xwithCpu}
-      ${xwithAbi}
-      ${xwithFpu}
-      ${xwithFloat}
-    '';
+        }"
+      ] ++
+      optional langAda "--enable-libada" ++
+      optional (xgccArch != null) "--with-arch=${xgccArch}" ++
+      optional (xgccCpu != null) "--with-cpu=${xgccCpu}" ++
+      optional (xgccAbi != null) "--with-abi=${xgccAbi}" ++
+      optional (xgccFpu != null) "--with-fpu=${xgccFpu}" ++
+      optional (xgccFloat != null) "--with-float=${xgccFloat}"
+    ;
     buildFlags = "";
   };
 
diff --git a/pkgs/development/compilers/gcc/snapshot/default.nix b/pkgs/development/compilers/gcc/snapshot/default.nix
index e235be639c6..ed127effd7e 100644
--- a/pkgs/development/compilers/gcc/snapshot/default.nix
+++ b/pkgs/development/compilers/gcc/snapshot/default.nix
@@ -98,108 +98,90 @@ let version = "7-20170409";
     javaAwtGtk = langJava && x11Support;
 
     /* Platform flags */
-    platformFlags = let
-        gccArch = stdenv.platform.gcc.arch or null;
-        gccCpu = stdenv.platform.gcc.cpu or null;
-        gccAbi = stdenv.platform.gcc.abi or null;
-        gccFpu = stdenv.platform.gcc.fpu or null;
-        gccFloat = stdenv.platform.gcc.float or null;
-        gccMode = stdenv.platform.gcc.mode or null;
-        withArch = if gccArch != null then " --with-arch=${gccArch}" else "";
-        withCpu = if gccCpu != null then " --with-cpu=${gccCpu}" else "";
-        withAbi = if gccAbi != null then " --with-abi=${gccAbi}" else "";
-        withFpu = if gccFpu != null then " --with-fpu=${gccFpu}" else "";
-        withFloat = if gccFloat != null then " --with-float=${gccFloat}" else "";
-        withMode = if gccMode != null then " --with-mode=${gccMode}" else "";
-      in
-        withArch +
-        withCpu +
-        withAbi +
-        withFpu +
-        withFloat +
-        withMode;
-
-    /* Cross-gcc settings */
+    mkPlatformFlags = platform: let
+        gccArch = platform.gcc.arch or null;
+        gccCpu = platform.gcc.cpu or null;
+        gccAbi = platform.gcc.abi or null;
+        gccFpu = platform.gcc.fpu or null;
+        gccFloat = platform.gcc.float or null;
+        gccMode = platform.gcc.mode or null;
+     in
+        optional (gccArch != null) "--with-arch=${gccArch}" ++
+        optional (gccCpu != null) "--with-cpu=${gccCpu}" ++
+        optional (gccAbi != null) "--with-abi=${gccAbi}" ++
+        optional (gccFpu != null) "--with-fpu=${gccFpu}" ++
+        optional (gccFloat != null) "--with-float=${gccFloat}" ++
+        optional (gccMode != null) "--with-mode=${gccMode}";
+
+    /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
     crossDarwin = targetPlatform != hostPlatform && targetPlatform.libc == "libSystem";
-    crossConfigureFlags = let
-        gccArch = targetPlatform.gcc.arch or null;
-        gccCpu = targetPlatform.gcc.cpu or null;
-        gccAbi = targetPlatform.gcc.abi or null;
-        gccFpu = targetPlatform.gcc.fpu or null;
-        gccFloat = targetPlatform.gcc.float or null;
-        gccMode = targetPlatform.gcc.mode or null;
-        withArch = if gccArch != null then " --with-arch=${gccArch}" else "";
-        withCpu = if gccCpu != null then " --with-cpu=${gccCpu}" else "";
-        withAbi = if gccAbi != null then " --with-abi=${gccAbi}" else "";
-        withFpu = if gccFpu != null then " --with-fpu=${gccFpu}" else "";
-        withFloat = if gccFloat != null then " --with-float=${gccFloat}" else "";
-        withMode = if gccMode != null then " --with-mode=${gccMode}" else "";
-      in
-        withArch +
-        withCpu +
-        withAbi +
-        withFpu +
-        withFloat +
-        withMode +
+    crossConfigureFlags =
+        mkPlatformFlags targetPlatform ++
+
         # Ensure that -print-prog-name is able to find the correct programs.
-        " --with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as" +
-        " --with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" +
+        [ "--with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as"
+          "--with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" ] ++
         (if crossMingw && crossStageStatic then
-          " --with-headers=${libcCross}/include" +
-          " --with-gcc" +
-          " --with-gnu-as" +
-          " --with-gnu-ld" +
-          " --with-gnu-ld" +
-          " --disable-shared" +
-          " --disable-nls" +
-          " --disable-debug" +
-          " --enable-sjlj-exceptions" +
-          " --enable-threads=win32" +
-          " --disable-win32-registry"
-          else if crossStageStatic then
-          " --disable-libssp --disable-nls" +
-          " --without-headers" +
-          " --disable-threads " +
-          " --disable-libgomp " +
-          " --disable-libquadmath" +
-          " --disable-shared" +
-          " --disable-libatomic " +  # libatomic requires libc
-          " --disable-decimal-float" # libdecnumber requires libc
-          else
-          (if crossDarwin then " --with-sysroot=${getLib libcCross}/share/sysroot"
-           else                " --with-headers=${getDev libcCross}/include") +
-          # Ensure that -print-prog-name is able to find the correct programs.
-          " --enable-__cxa_atexit" +
-          " --enable-long-long" +
-          (if crossMingw then
-            " --enable-threads=win32" +
-            " --enable-sjlj-exceptions" +
-            " --enable-hash-synchronization" +
-            " --disable-libssp" +
-            " --disable-nls" +
-            " --with-dwarf2" +
+          [ "--with-headers=${libcCross}/include"
+            "--with-gcc"
+            "--with-gnu-as"
+            "--with-gnu-ld"
+            "--with-gnu-ld"
+            "--disable-shared"
+            "--disable-nls"
+            "--disable-debug"
+            "--enable-sjlj-exceptions"
+            "--enable-threads=win32"
+            "--disable-win32-registry"
+          ] else if crossStageStatic then
+          [ "--disable-libssp"
+            "--disable-nls"
+            "--without-headers"
+            "--disable-threads "
+            "--disable-libgomp "
+            "--disable-libquadmath"
+            "--disable-shared"
+            "--disable-libatomic "  # libatomic requires libc
+            "--disable-decimal-float" # libdecnumber requires libc
+          ] else
+            (if crossDarwin then ["--with-sysroot=${getLib libcCross}/share/sysroot"]
+             else                ["--with-headers=${getDev libcCross}/include"]) ++
+          [ "--enable-__cxa_atexit"
+            "--enable-long-long"
+          ] ++
+
+          (if crossMingw then [
+            "--enable-threads=win32"
+            "--enable-sjlj-exceptions"
+            "--enable-hash-synchronization"
+            "--disable-libssp"
+            "--disable-nls"
+            "--with-dwarf2"
             # I think noone uses shared gcc libs in mingw, so we better do the same.
             # In any case, mingw32 g++ linking is broken by default with shared libs,
             # unless adding "-lsupc++" to any linking command. I don't know why.
-            " --disable-shared" +
+            "--disable-shared"
             # To keep ABI compatibility with upstream mingw-w64
-            " --enable-fully-dynamic-string"
-            else (if targetPlatform.libc == "uclibc" then
+            "--enable-fully-dynamic-string"
+          ] else
+            optionals (targetPlatform.libc == "uclibc") [
               # libsanitizer requires netrom/netrom.h which is not
               # available in uclibc.
-              " --disable-libsanitizer" +
+              "--disable-libsanitizer"
               # In uclibc cases, libgomp needs an additional '-ldl'
               # and as I don't know how to pass it, I disable libgomp.
-              " --disable-libgomp" else "") +
-            " --enable-threads=posix" +
-            " --enable-nls" +
-            " --disable-decimal-float") # No final libdecnumber (it may work only in 386)
+              "--disable-libgomp"
+            ] ++
+            [ "--enable-threads=posix"
+              "--enable-nls"
+              "--disable-decimal-float" # No final libdecnumber (it may work only in 386)
+            ])
           );
     stageNameAddon = if crossStageStatic then "-stage-static" else "-stage-final";
     crossNameAddon = if targetPlatform != hostPlatform then "-${targetPlatform.config}" + stageNameAddon else "";
 
-  bootstrap = targetPlatform == hostPlatform;
+    bootstrap = targetPlatform == hostPlatform;
 
 in
 
@@ -322,62 +304,86 @@ stdenv.mkDerivation ({
     then []
     else [ "build" "host" ] ++ stdenv.lib.optional (targetPlatform != hostPlatform) "target";
 
-  configureFlags = "
-    ${if hostPlatform.isSunOS then
-      " --enable-long-long --enable-libssp --enable-threads=posix --disable-nls --enable-__cxa_atexit " +
-      # On Illumos/Solaris GNU as is preferred
-      " --with-gnu-as --without-gnu-ld "
-      else ""}
-    --enable-lto
-    ${if enableMultilib then "--enable-multilib --disable-libquadmath" else "--disable-multilib"}
-    ${if enableShared then "" else "--disable-shared"}
-    ${if enablePlugin then "--enable-plugin" else "--disable-plugin"}
-    ${optionalString (isl != null) "--with-isl=${isl}"}
-    ${if langJava then
-      "--with-ecj-jar=${javaEcj} " +
+  configureFlags =
+    # Basic dependencies
+    [
+      "--with-gmp-include=${gmp.dev}/include"
+      "--with-gmp-lib=${gmp.out}/lib"
+      "--with-mpfr-include=${mpfr.dev}/include"
+      "--with-mpfr-lib=${mpfr.out}/lib"
+      "--with-mpc=${libmpc}"
+    ] ++
+    optional (libelf != null) "--with-libelf=${libelf}" ++
+
+    # Basic configuration
+    [
+      "--enable-lto"
+      "--disable-libstdcxx-pch"
+      "--without-included-gettext"
+      "--with-system-zlib"
+      "--enable-static"
+      "--enable-languages=${
+        concatStrings (intersperse ","
+          (  optional langC        "c"
+          ++ optional langCC       "c++"
+          ++ optional langFortran  "fortran"
+          ++ optional langJava     "java"
+          ++ optional langAda      "ada"
+          ++ optional langVhdl     "vhdl"
+          ++ optional langGo       "go"
+          ++ optional langObjC     "objc"
+          ++ optional langObjCpp   "obj-c++"
+          ++ optionals crossDarwin [ "objc" "obj-c++" ]
+          )
+        )
+      }"
+    ] ++
+
+    (if enableMultilib
+      then ["--enable-multilib" "--disable-libquadmath"]
+      else ["--disable-multilib"]) ++
+    optional (!enableShared) "--disable-shared" ++
+    (if enablePlugin
+      then ["--enable-plugin"]
+      else ["--disable-plugin"]) ++
+
+    # Optional features
+    optional (isl != null) "--with-isl=${isl}" ++
+
+    # Java options
+    optionals langJava [
+      "--with-ecj-jar=${javaEcj} "
 
       # Follow Sun's layout for the convenience of IcedTea/OpenJDK.  See
       # <http://mail.openjdk.java.net/pipermail/distro-pkg-dev/2010-April/008888.html>.
       "--enable-java-home --with-java-home=\${prefix}/lib/jvm/jre "
-      else ""}
-    ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-    ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr}" else ""}
-    --with-gmp-include=${gmp.dev}/include
-    --with-gmp-lib=${gmp.out}/lib
-    --with-mpfr-include=${mpfr.dev}/include
-    --with-mpfr-lib=${mpfr.out}/lib
-    --with-mpc=${libmpc}
-    ${if libelf != null then "--with-libelf=${libelf}" else ""}
-    --disable-libstdcxx-pch
-    --without-included-gettext
-    --with-system-zlib
-    --enable-static
-    --enable-languages=${
-      concatStrings (intersperse ","
-        (  optional langC        "c"
-        ++ optional langCC       "c++"
-        ++ optional langFortran  "fortran"
-        ++ optional langJava     "java"
-        ++ optional langAda      "ada"
-        ++ optional langVhdl     "vhdl"
-        ++ optional langGo       "go"
-        ++ optional langObjC     "objc"
-        ++ optional langObjCpp   "obj-c++"
-        ++ optionals crossDarwin [ "objc" "obj-c++" ]
-        )
-      )
-    }
-    ${if targetPlatform == hostPlatform
-      then if hostPlatform.isDarwin
-        then " --with-native-system-header-dir=${darwin.usr-include}"
-        else " --with-native-system-header-dir=${getDev stdenv.cc.libc}/include"
-      else ""}
-    ${if langAda then " --enable-libada" else ""}
-    ${if targetPlatform == hostPlatform && targetPlatform.isi686 then "--with-arch=i686" else ""}
-    ${if targetPlatform != hostPlatform then crossConfigureFlags else ""}
-    ${if !bootstrap then "--disable-bootstrap" else ""}
-    ${if targetPlatform == hostPlatform then platformFlags else ""}
-  ";
+    ] ++
+    optional javaAwtGtk "--enable-java-awt=gtk" ++
+    optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr}" ++
+
+    # Ada
+    optional langAda "--enable-libada" ++
+
+    # Cross-compilation
+    optional (targetPlatform == hostPlatform) (
+      let incDir = if hostPlatform.isDarwin
+                     then "${darwin.usr-include}"
+                     else "${getDev stdenv.cc.libc}/include";
+      in "--with-native-system-header-dir=${incDir}"
+    ) ++
+
+    optional (targetPlatform == hostPlatform) (mkPlatformFlags stdenv.platform) ++
+    optional (targetPlatform != hostPlatform) crossConfigureFlags ++
+    optional (!bootstrap) "--disable-bootstrap" ++
+
+    # Platform-specific flags
+    optional (targetPlatform == hostPlatform && targetPlatform.isi686) "--with-arch=i686" ++
+    optionals hostPlatform.isSunOS [
+      "--enable-long-long --enable-libssp --enable-threads=posix --disable-nls --enable-__cxa_atexit"
+      # On Illumos/Solaris GNU as is preferred
+      "--with-gnu-as --without-gnu-ld"
+    ]
+  ;
 
   targetConfig = if targetPlatform != hostPlatform then targetPlatform.config else null;
 
@@ -390,17 +396,13 @@ stdenv.mkDerivation ({
     then "install-strip"
     else "install";
 
+  /* For cross-built gcc (build != host == target) */
   crossAttrs = let
     xgccArch = targetPlatform.gcc.arch or null;
     xgccCpu = targetPlatform.gcc.cpu or null;
     xgccAbi = targetPlatform.gcc.abi or null;
     xgccFpu = targetPlatform.gcc.fpu or null;
     xgccFloat = targetPlatform.gcc.float or null;
-    xwithArch = if xgccArch != null then " --with-arch=${xgccArch}" else "";
-    xwithCpu = if xgccCpu != null then " --with-cpu=${xgccCpu}" else "";
-    xwithAbi = if xgccAbi != null then " --with-abi=${xgccAbi}" else "";
-    xwithFpu = if xgccFpu != null then " --with-fpu=${xgccFpu}" else "";
-    xwithFloat = if xgccFloat != null then " --with-float=${xgccFloat}" else "";
   in {
     AR = "${targetPlatform.config}-ar";
     LD = "${targetPlatform.config}-ld";
@@ -414,37 +416,39 @@ stdenv.mkDerivation ({
     # If we are making a cross compiler, cross != null
     NIX_CC_CROSS = optionalString (targetPlatform == hostPlatform) builtins.toString stdenv.cc;
     dontStrip = true;
-    configureFlags = ''
-      ${if enableMultilib then "" else "--disable-multilib"}
-      ${if enableShared then "" else "--disable-shared"}
-      ${if langJava then "--with-ecj-jar=${javaEcj.crossDrv}" else ""}
-      ${if javaAwtGtk then "--enable-java-awt=gtk" else ""}
-      ${if langJava && javaAntlr != null then "--with-antlr-jar=${javaAntlr.crossDrv}" else ""}
-      --with-gmp=${gmp.crossDrv}
-      --with-mpfr=${mpfr.crossDrv}
-      --with-mpc=${libmpc.crossDrv}
-      --disable-libstdcxx-pch
-      --without-included-gettext
-      --with-system-zlib
-      --enable-languages=${
-        concatStrings (intersperse ","
-          (  optional langC        "c"
-          ++ optional langCC       "c++"
-          ++ optional langFortran  "fortran"
-          ++ optional langJava     "java"
-          ++ optional langAda      "ada"
-          ++ optional langVhdl     "vhdl"
-          ++ optional langGo       "go"
+    configureFlags =
+      optional (!enableMultilib) "--disable-multilib" ++
+      optional (!enableShared) "--disable-shared" ++
+      optional langJava "--with-ecj-jar=${javaEcj.crossDrv}" ++
+      optional javaAwtGtk "--enable-java-awt=gtk" ++
+      optional (langJava && javaAntlr != null) "--with-antlr-jar=${javaAntlr.crossDrv}" ++
+      [
+        "--with-gmp=${gmp.crossDrv}"
+        "--with-mpfr=${mpfr.crossDrv}"
+        "--with-mpc=${libmpc.crossDrv}"
+        "--disable-libstdcxx-pch"
+        "--without-included-gettext"
+        "--with-system-zlib"
+        "--enable-languages=${
+          concatStrings (intersperse ","
+            (  optional langC        "c"
+            ++ optional langCC       "c++"
+            ++ optional langFortran  "fortran"
+            ++ optional langJava     "java"
+            ++ optional langAda      "ada"
+            ++ optional langVhdl     "vhdl"
+            ++ optional langGo       "go"
+            )
           )
-        )
-      }
-      ${if langAda then " --enable-libada" else ""}
-      ${xwithArch}
-      ${xwithCpu}
-      ${xwithAbi}
-      ${xwithFpu}
-      ${xwithFloat}
-    '';
+        }"
+      ] ++
+      optional langAda "--enable-libada" ++
+      optional (xgccArch != null) "--with-arch=${xgccArch}" ++
+      optional (xgccCpu != null) "--with-cpu=${xgccCpu}" ++
+      optional (xgccAbi != null) "--with-abi=${xgccAbi}" ++
+      optional (xgccFpu != null) "--with-fpu=${xgccFpu}" ++
+      optional (xgccFloat != null) "--with-float=${xgccFloat}"
+    ;
     buildFlags = "";
   };