gcc: fix darwin dispatch/object.h header issue (#1518)

Fixes #1203. Apple ships headers in Yosemite (and possibly earlier) that
are gcc-incompatible, but compile fine with clang. The fix is to copy
the offending system header from /usr/include/${REST_OF_HEADER_PATH} to
${GCC_PREFIX}/include/${REST_OF_HEADER_PATH} and replace the non-gcc-
compatible features with gcc-compatible equivalents.

See https://github.com/hashdist/hashstack/pull/771/files for
inspiration, and
http://hamelot.io/programming/osx-gcc-dispatch_block_t-has-not-been-declared-invalid-typedef/
for a description of the header issue.

1 files changed, 14 insertions, 0 deletions

diff --git a/var/spack/repos/builtin/packages/gcc/package.py b/var/spack/repos/builtin/packages/gcc/package.py
index 3be3948b59..d152ce61c7 100644
--- a/var/spack/repos/builtin/packages/gcc/package.py
+++ b/var/spack/repos/builtin/packages/gcc/package.py
@@ -3,6 +3,7 @@ from spack import *
 from contextlib import closing
 from glob import glob
 import sys
+from os.path import isfile
 
 
 class Gcc(Package):
@@ -68,6 +69,19 @@ class Gcc(Package):
         if spec.satisfies("@4.7.1:") and sys.platform != 'darwin':
             enabled_languages.add('go')
 
+        # Fix a standard header file for OS X Yosemite that
+        # is GCC incompatible by replacing non-GCC compliant macros
+        if 'yosemite' in spec.architecture:
+            if isfile(r'/usr/include/dispatch/object.h'):
+                new_dispatch_dir = join_path(prefix, 'include', 'dispatch')
+                mkdirp(new_dispatch_dir)
+                cp = which('cp')
+                new_header = join_path(new_dispatch_dir, 'object.h')
+                cp(r'/usr/include/dispatch/object.h', new_header)
+                filter_file(r'typedef void \(\^dispatch_block_t\)\(void\)',
+                            'typedef void* dispatch_block_t',
+                            new_header)
+
         # Generic options to compile GCC
         options = ["--prefix=%s" % prefix, "--libdir=%s/lib64" % prefix,
                    "--disable-multilib",