build/common.gypi: revert the change to GCC_STRICT_ALIASING:NO because some bots have a too-old xco…

build/common.gypi

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 3963 matching lines @@
             }],
           ],
         },
         'xcode_settings': {
           'GCC_DYNAMIC_NO_PIC': 'NO',               # No -mdynamic-no-pic
                                                     # (Equivalent to -fPIC)
           # MACOSX_DEPLOYMENT_TARGET maps to -mmacosx-version-min
           'MACOSX_DEPLOYMENT_TARGET': '<(mac_deployment_target)',
           # Keep pch files below xcodebuild/.
           'SHARED_PRECOMPS_DIR': '$(CONFIGURATION_BUILD_DIR)/SharedPrecompiledHeaders',
-
-          # -fno-strict-aliasing, see http://crbug.com/32204
-          'GCC_STRICT_ALIASING': 'NO',
+          'OTHER_CFLAGS': [
+            # Someday this can be replaced by an 'GCC_STRICT_ALIASING': 'NO'
+            # xcode_setting, but not until all downstream projects' mac bots are
+            # using xcode >= 4.6, because that's when the default value of the
+            # flag in the compiler switched.  Pre-4.6, the value 'NO' for that
+            # setting is a no-op as far as xcode is concerned, but the compiler
+            # behaves differently based on whether -fno-strict-aliasing is
+            # specified or not.
+            '-fno-strict-aliasing',  # See http://crbug.com/32204.
+          ],
         },
         'target_conditions': [
           ['_type=="executable"', {
             'postbuilds': [
               {
                 # Arranges for data (heap) pages to be protected against
                 # code execution when running on Mac OS X 10.7 ("Lion"), and
                 # ensures that the position-independent executable (PIE) bit
                 # is set for ASLR when running on Mac OS X 10.5 ("Leopard").
                 'variables': {
@@ skipping 641 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }