lib.systems.parsed: add "elf" for some NetBSD archs

In Autoconf, some old NetBSD targets like "i686-unknown-netbsd" are
interpreted as a.out, not elf, and virtually nothing supports it.  We
need to specify e.g. "i686-unknown-netbsdelf" to get the right
behaviour.

1 files changed, 13 insertions, 1 deletions

diff --git a/lib/systems/parse.nix b/lib/systems/parse.nix
index b27d37f55ae..2b789fd8ecb 100644
--- a/lib/systems/parse.nix
+++ b/lib/systems/parse.nix
@@ -121,6 +121,14 @@ rec {
     js       = { bits = 32; significantByte = littleEndian; family = "js"; };
   };
 
+  # GNU build systems assume that older NetBSD architectures are using a.out.
+  gnuNetBSDDefaultExecFormat = cpu:
+    if (cpu.family == "x86" && cpu.bits == 32) ||
+       (cpu.family == "arm" && cpu.bits == 32) ||
+       (cpu.family == "sparc" && cpu.bits == 32)
+    then execFormats.aout
+    else execFormats.elf;
+
   # Determine when two CPUs are compatible with each other. That is,
   # can code built for system B run on system A? For that to happen,
   # the programs that system B accepts must be a subset of the
@@ -463,8 +471,12 @@ rec {
     else "${cpu.name}-${kernel.name}";
 
   tripleFromSystem = { cpu, vendor, kernel, abi, ... } @ sys: assert isSystem sys; let
+    optExecFormat =
+      lib.optionalString (kernel.name == "netbsd" &&
+                          gnuNetBSDDefaultExecFormat cpu != kernel.execFormat)
+        kernel.execFormat.name;
     optAbi = lib.optionalString (abi != abis.unknown) "-${abi.name}";
-  in "${cpu.name}-${vendor.name}-${kernel.name}${optAbi}";
+  in "${cpu.name}-${vendor.name}-${kernel.name}${optExecFormat}${optAbi}";
 
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