xcode: Drop use of weak_import on enumerators.

GCC doesn't support attributes on enumerators, which could pose a
problem but fortunately not in this case. Here a
__attribute__((weak_import)) is used, which doesn't make much sense for
enumerators anyway (noone will die because the corresponding enumerator
won't be referenced either in older OS X versions).

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/os-specific/darwin/xcode/default.nix

@@ -1,6 +1,10 @@
 { stdenv, requireFile, xpwn }:
 
-stdenv.mkDerivation rec {
+with stdenv.lib;
+
+let
+  osxVersion = "10.9";
+in stdenv.mkDerivation rec {
   name = "xcode-${version}";
   version = "5.0.2";
 
@@ -10,9 +14,10 @@ stdenv.mkDerivation rec {
     sha256 = "0mrligqkfqwx8cy883pxm4w5w7a17nfh227zdspfll23r9agf32k";
   };
 
-  phases = [ "unpackPhase" "installPhase" "fixupPhase" ];
+  phases = [ "unpackPhase" "patchPhase" "installPhase" "fixupPhase" ];
   outputs = [ "out" "toolchain" ];
 
+
   unpackCmd = let
     basePath = "Xcode.app/Contents/Developer/Platforms/MacOSX.platform";
     sdkPath = "${basePath}/Developer/SDKs";
@@ -21,7 +26,9 @@ stdenv.mkDerivation rec {
     ${xpwn}/bin/hfsplus main.hfs extractall "${sdkPath}" > /dev/null
   '';
 
-  setSourceRoot = "sourceRoot=MacOSX10.9.sdk";
+  setSourceRoot = "sourceRoot=MacOSX${osxVersion}.sdk";
+
+  patches = optional (osxVersion == "10.9") ./gcc-fix-enum-attributes.patch;
 
   installPhase = ''
     ensureDir "$out/share/sysroot"