Add support for GCC_WARN_ABOUT_INVALID_OFFSETOF_MACRO to xcode emulation.

pylib/gyp/xcode_emulation.py

 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 This module contains classes that help to emulate xcodebuild behavior on top of
 other build systems, such as make and ninja.
 """
 
 import gyp.common
@@ skipping 342 matching lines @@
     self.configname = configname
     cflags_cc = []
     if self._Test('GCC_ENABLE_CPP_RTTI', 'NO', default='YES'):
       cflags_cc.append('-fno-rtti')
     if self._Test('GCC_ENABLE_CPP_EXCEPTIONS', 'NO', default='YES'):
       cflags_cc.append('-fno-exceptions')
     if self._Test('GCC_INLINES_ARE_PRIVATE_EXTERN', 'YES', default='NO'):
       cflags_cc.append('-fvisibility-inlines-hidden')
     if self._Test('GCC_THREADSAFE_STATICS', 'NO', default='YES'):
       cflags_cc.append('-fno-threadsafe-statics')
+    if self._Test('GCC_WARN_ABOUT_INVALID_OFFSETOF_MACRO', 'NO', default='YES'):
+      cflags_cc.append('-Wno-invalid-offsetof')
 
     other_ccflags = []
 
     for flag in self._Settings().get('OTHER_CPLUSPLUSFLAGS', ['$(inherited)']):
       # TODO: More general variable expansion. Missing in many other places too.
       if flag in ('$inherited', '$(inherited)', '${inherited}'):
         flag = '$OTHER_CFLAGS'
       if flag in ('$OTHER_CFLAGS', '$(OTHER_CFLAGS)', '${OTHER_CFLAGS}'):
         other_ccflags += self._Settings().get('OTHER_CFLAGS', [])
       else:
@@ skipping 646 matching lines @@
 def GetSpecPostbuildCommands(spec, quiet=False):
   """Returns the list of postbuilds explicitly defined on |spec|, in a form
   executable by a shell."""
   postbuilds = []
   for postbuild in spec.get('postbuilds', []):
     if not quiet:
       postbuilds.append('echo POSTBUILD\\(%s\\) %s' % (
             spec['target_name'], postbuild['postbuild_name']))
     postbuilds.append(gyp.common.EncodePOSIXShellList(postbuild['action']))
   return postbuilds