6 files changed, 36 insertions, 12 deletions
diff --git a/pkgs/build-support/bintools-wrapper/default.nix b/pkgs/build-support/bintools-wrapper/default.nix
index 2739537c25d..91f9e7c71e3 100644
--- a/pkgs/build-support/bintools-wrapper/default.nix
+++ b/pkgs/build-support/bintools-wrapper/default.nix
@@ -185,6 +185,8 @@ stdenv.mkDerivation {
           "mips64"   = "btsmip";
           "mips64el" = "ltsmip";
         }.${targetPlatform.parsed.cpu.name}
+      else if targetPlatform.isPowerPC then "powerpc"
+      else if targetPlatform.isSparc then "sparc"
       else throw "unknown emulation for platform: " + targetPlatform.config;
     in targetPlatform.platform.bfdEmulation or (fmt + sep + arch);
 
diff --git a/pkgs/build-support/bintools-wrapper/setup-hook.sh b/pkgs/build-support/bintools-wrapper/setup-hook.sh
index 025f6aa6e7a..f65b792485a 100644
--- a/pkgs/build-support/bintools-wrapper/setup-hook.sh
+++ b/pkgs/build-support/bintools-wrapper/setup-hook.sh
@@ -20,7 +20,13 @@ bintoolsWrapper_addLDVars () {
     fi
 
     if [[ -d "$1/lib" ]]; then
-        export NIX_${role_pre}LDFLAGS+=" -L$1/lib"
+        # Don't add the /lib directory if it actually doesn't contain any libraries. For instance,
+        # Python and Haskell packages often only have directories like $out/lib/ghc-8.4.3/ or
+        # $out/lib/python3.6/, so having them in LDFLAGS just makes the linker search unnecessary
+        # directories and bloats the size of the environment variable space.
+        if [[ -n "$(echo $1/lib/lib*)" ]]; then
+            export NIX_${role_pre}LDFLAGS+=" -L$1/lib"
+        fi
     fi
 }
 
diff --git a/pkgs/build-support/build-maven.nix b/pkgs/build-support/build-maven.nix
index 30df3e8e733..b9da06c43c8 100644
--- a/pkgs/build-support/build-maven.nix
+++ b/pkgs/build-support/build-maven.nix
@@ -16,10 +16,11 @@ infoFile: let
   script = writeText "build-maven-repository.sh" ''
     ${lib.concatStrings (map (dep: let
       inherit (dep)
-        url sha1 groupId artifactId version
-        authenticated metadata repository-id;
+        url sha1 groupId artifactId
+        version metadata repository-id;
 
       versionDir = dep.unresolved-version or version;
+      authenticated = dep.authenticated or false;
 
       fetch = (if authenticated then requireFile else fetchurl) {
         inherit url sha1;
diff --git a/pkgs/build-support/docker/default.nix b/pkgs/build-support/docker/default.nix
index 950c0c86a6e..bc79f9ff12f 100644
--- a/pkgs/build-support/docker/default.nix
+++ b/pkgs/build-support/docker/default.nix
@@ -36,10 +36,11 @@ rec {
   in
     { imageName
       # To find the digest of an image, you can use skopeo:
-      # skopeo inspect docker://docker.io/nixos/nix:1.11 | jq -r '.Digest'
-      # sha256:20d9485b25ecfd89204e843a962c1bd70e9cc6858d65d7f5fadc340246e2116b
+      # see doc/functions.xml
     , imageDigest
     , sha256
+    , os ? "linux"
+    , arch ? "x86_64"
       # This used to set a tag to the pulled image
     , finalImageTag ? "latest"
     , name ? fixName "docker-image-${imageName}-${finalImageTag}.tar"
@@ -59,7 +60,7 @@ rec {
       sourceURL = "docker://${imageName}@${imageDigest}";
       destNameTag = "${imageName}:${finalImageTag}";
     } ''
-      skopeo copy "$sourceURL" "docker-archive://$out:$destNameTag"
+      skopeo --override-os ${os} --override-arch ${arch} copy "$sourceURL" "docker-archive://$out:$destNameTag"
     '';
 
   # We need to sum layer.tar, not a directory, hence tarsum instead of nix-hash.
diff --git a/pkgs/build-support/emacs/melpa.nix b/pkgs/build-support/emacs/melpa.nix
index 5fa45b154a3..2ee99ce973e 100644
--- a/pkgs/build-support/emacs/melpa.nix
+++ b/pkgs/build-support/emacs/melpa.nix
@@ -5,7 +5,15 @@
 
 with lib;
 
-{ pname
+{ /*
+    pname: Nix package name without special symbols and without version or
+    "emacs-" prefix.
+  */
+  pname
+  /*
+    ename: Original Emacs package name, possibly containing special symbols.
+  */
+, ename ? null
 , version
 , recipe
 , meta ? {}
@@ -22,6 +30,11 @@ in
 
 import ./generic.nix { inherit lib stdenv emacs texinfo; } ({
 
+  ename =
+    if isNull(ename)
+    then pname
+    else ename;
+
   melpa = fetchFromGitHub {
     owner = "melpa";
     repo = "melpa";
@@ -35,7 +48,7 @@ import ./generic.nix { inherit lib stdenv emacs texinfo; } ({
   preUnpack = ''
     mkdir -p "$NIX_BUILD_TOP/recipes"
     if [ -n "$recipe" ]; then
-      cp "$recipe" "$NIX_BUILD_TOP/recipes/$pname"
+      cp "$recipe" "$NIX_BUILD_TOP/recipes/$ename"
     fi
 
     ln -s "$melpa/package-build" "$NIX_BUILD_TOP/package-build"
@@ -45,7 +58,7 @@ import ./generic.nix { inherit lib stdenv emacs texinfo; } ({
 
   postUnpack = ''
     mkdir -p "$NIX_BUILD_TOP/working"
-    ln -s "$NIX_BUILD_TOP/$sourceRoot" "$NIX_BUILD_TOP/working/$pname"
+    ln -s "$NIX_BUILD_TOP/$sourceRoot" "$NIX_BUILD_TOP/working/$ename"
   '';
 
   buildPhase =
@@ -58,7 +71,7 @@ import ./generic.nix { inherit lib stdenv emacs texinfo; } ({
           -L "$melpa/package-build" \
           -l "$melpa2nix" \
           -f melpa2nix-build-package \
-          $pname $version
+          $ename $version
 
       runHook postBuild
     '';
@@ -66,9 +79,9 @@ import ./generic.nix { inherit lib stdenv emacs texinfo; } ({
   installPhase = ''
     runHook preInstall
 
-    archive="$NIX_BUILD_TOP/packages/$pname-$version.el"
+    archive="$NIX_BUILD_TOP/packages/$ename-$version.el"
     if [ ! -f "$archive" ]; then
-        archive="$NIX_BUILD_TOP/packages/$pname-$version.tar"
+        archive="$NIX_BUILD_TOP/packages/$ename-$version.tar"
     fi
 
     emacs --batch -Q \
diff --git a/pkgs/build-support/setup-hooks/remove-pytest-cache.sh b/pkgs/build-support/setup-hooks/remove-pytest-cache.sh
new file mode 100644
index 00000000000..7f3e08bfa67
--- /dev/null
+++ b/pkgs/build-support/setup-hooks/remove-pytest-cache.sh
@@ -0,0 +1 @@
+postFixupHooks+=