enable -Wstring-conversion when compiling with clang

third_party/mesa/mesa.gyp

 # 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.
 
 {
   'variables': {
     # Disable warnings as errors for mesa until they're fixed or disabled.
     # http://crbug.com/143877
     'win_third_party_warn_as_error': 'false',
   },
@@ skipping 525 matching lines @@
           'conditions': [
             ['clang == 1', {
               'xcode_settings': {
                 'WARNING_CFLAGS': [
                   # Several functions ignore the result of talloc_steal().
                   '-Wno-unused-value',
                   # texenvprogram.c converts '~0' to a bitfield, which causes clang
                   # to warn that -1 is implicitly converted to 255.
                   '-Wno-constant-conversion',
                 ],
+                'WARNING_CFLAGS!': [
+                  # Don't warn about string->bool used in asserts.
+                  '-Wstring-conversion',
+                ],
               },
               'cflags': [
                 '-Wno-unused-value',
                 '-Wno-constant-conversion',
               ],
+              'cflags!': [
+                '-Wstring-conversion',
+              ],
             }],
           ],
         },
         # Building this target will hide the native OpenGL shared library and
         # replace it with a slow software renderer.
         {
           'target_name': 'osmesa',
           'type': 'loadable_module',
           'mac_bundle': 0,
           'dependencies': [
@@ skipping 61 matching lines @@
           'type': 'none',
         },
         {
           'target_name': 'osmesa',
           'type': 'none',
         },
       ],
     }],
   ],
 }