Fix warnings that were exposed when running with SK_DEBUG enable on an optimized release build.

gyp/common.gypi

 # Copyright 2011 The Android Open Source Project
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 #
 # This file is automatically included by gyp_skia when building any target.
 
 {
   'includes': [
     'common_variables.gypi',
@@ skipping 84 matching lines @@
       [ 'skia_android_framework==0', {
         # These defines are not used for skia_android_framework, where we build
         # one makefile and allow someone to add SK_DEBUG etc for their own
         # debugging purposes.
         'configurations': {
           'Debug':   { 'defines': [ 'SK_DEBUG=1' ] },
           'Release': { 'defines': [ 'NDEBUG' ] },
           'Release_Developer': {
             'inherit_from': ['Release'],
             'defines': [ 'SK_DEBUG=1' ],
+            'conditions': [
+              [ 'skia_clang_build == 0', {
+                # gcc has problems providing useful warnings of these types for
+                # optimized builds.
+                'cflags': [
+                  '-Wno-maybe-uninitialized',
+                  '-Wno-strict-overflow',
+                ],
+              }],
+            ],
           },
         },
       }],
     ],
   }, # end 'target_defaults'
 }