Enable building ppapi/examples on Mac.

ppapi/ppapi_gl.gypi

 # Copyright (c) 2010 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.
 
 {
   'includes': [
     '../third_party/mesa/mesa.gypi',
   ],
   'targets': [
     {
@@ skipping 14 matching lines @@
         '_EGL_PLATFORM_PPAPI=_EGL_NUM_PLATFORMS',
         '_EGL_NATIVE_PLATFORM=_EGL_PLATFORM_PPAPI',
       ],
       'conditions': [
         ['OS=="win"', {
           'defines': [
             '_EGL_OS_WINDOWS',
           ],
         }],
         ['OS=="mac"', {
-          # TODO(alokp): Make this compile on mac.
           'suppress_wildcard': 1,
+          'xcode_settings': {
+            # Suppress warnings in third party mesa_egl code.
+            'WARNING_CFLAGS': ['-Wno-sign-compare']
+          }
         }],
       ],
       'sources': [
         # Mesa EGL API dispatcher sources.
         '<@(mesa_egl_sources)',
         # PPAPI EGL driver sources.
         'lib/gl/egl/egldriver.c',
         'lib/gl/egl/egldriver_ppapi.c',
       ],
     },
     {
       'target_name': 'ppapi_gles2',
       'type': 'static_library',
       'dependencies': [
         'ppapi_c',
       ],
       'include_dirs': [
         'lib/gl/include',
       ],
       'sources': [
         'lib/gl/gles2/gl2ext_ppapi.c',
         'lib/gl/gles2/gl2ext_ppapi.h',
         'lib/gl/gles2/gles2.c',
       ],
     },
   ],
 }