gcc: add linkLib32toLib to create lib32->lib links

Our gcc builder creates lib64->lib links to ensure that the "primary"
libraries for the targetPlatform wind up in $PREFIX/lib.  This is
required in order for make-bootstrap-files.nix to work correctly.

On mips, gcc follows the somewhat awkward IRIX convention of putting
mips32 binaries in `lib` and mips64n32 binaries in `lib32`.  So we
need similar symlinks there.  This may come up on other ILP32
platforms as well, so a general-purpose variable name is provided.

pkgs/development/compilers/gcc/builder.sh

@@ -197,6 +197,11 @@ preInstall() {
         ln -s lib "$out/${targetConfig}/lib64"
         ln -s lib "${!outputLib}/${targetConfig}/lib64"
     fi
+    # Make ‘lib32’ symlinks to ‘lib’.
+    if [ -n "$linkLib32toLib" ]; then
+        ln -s lib "$out/${targetConfig}/lib32"
+        ln -s lib "${!outputLib}/${targetConfig}/lib32"
+    fi
 }
 
 

pkgs/development/compilers/gcc/common/pre-configure.nix

@@ -78,3 +78,13 @@ in lib.optionalString (hostPlatform.isSunOS && hostPlatform.is64bit) ''
 + lib.optionalString (targetPlatform != hostPlatform && crossStageStatic) ''
   export inhibit_libc=true
 ''
+
+# On mips platforms, gcc follows the IRIX naming convention:
+#
+#  $PREFIX/lib   = mips32
+#  $PREFIX/lib32 = mips64n32
+#  $PREFIX/lib64 = mips64
+#
++ lib.optionalString (targetPlatform.isMips64n32) ''
+  export linkLib32toLib=1
+''