Use no_strict_aliasing=1 by default.

build/common.gypi

 # Copyright (c) 2009 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': {
     # .gyp files should set chromium_code to 1 if they build Chromium-specific
@@ skipping 562 matching lines @@
         }],
       ],
     },
   },
   'conditions': [
     ['OS=="linux" or OS=="freebsd" or OS=="openbsd"', {
       'target_defaults': {
         # Enable -Werror by default, but put it in a variable so it can
         # be disabled in ~/.gyp/include.gypi on the valgrind builders.
         'variables': {
-          'no_strict_aliasing%': 0,
+          # Use -fno-strict-aliasing by default since gcc 4.4 has periodic
+          # issues that slip through the cracks. We could do this just for
+          # gcc 4.4 but it makes more sense to be consistent on all
+          # compilers in use. TODO(Craig): turn this off again when
+          # there is some 4.4 test infrastructure in place and existing
+          # aliasing issues have been fixed.
+          'no_strict_aliasing%': 1,
           'conditions': [['OS=="linux"', {'werror%': '-Werror',}],
                          ['OS=="freebsd"', {'werror%': '',}],
                          ['OS=="openbsd"', {'werror%': '',}],
           ],
         },
         'cflags': [
           '<(werror)',  # See note above about the werror variable.
           '-pthread',
           '-fno-exceptions',
           '-Wall',
@@ skipping 563 matching lines @@
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }
 
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