Fix build warnings with gcc4.8

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 2676 matching lines @@
           },
           'profile': {
             'cflags': ['-pg', '-g'],
             'ldflags': ['-pg'],
           },
           'symbols': {
             'cflags': ['-g'],
           },
         },
         'conditions': [
+          # Don't warn about the "typedef 'foo' locally defined but not used"
+          # for gcc 4.8.
+          # TODO: remove this flag once all builds work. See crbug.com/227506
+          [ 'gcc_version>=48', {
+            'cflags': [
+              '-Wno-unused-local-typedefs',
+            ],
+          }],
           ['target_arch=="ia32"', {
             'target_conditions': [
               ['_toolset=="target"', {
                 'asflags': [
                   # Needed so that libs with .s files (e.g. libicudata.a)
                   # are compatible with the general 32-bit-ness.
                   '-32',
                 ],
                 # All floating-point computations on x87 happens in 80-bit
                 # precision.  Because the C and C++ language standards allow
@@ skipping 1515 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',
   },
 }