Make use_system_mesa switch work: make symlinks

third_party/khronos/khronos.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': {
-    'use_system_khronos%': 0,
-  },
   'conditions': [
-    ['use_system_khronos==0', {
+    ['use_system_mesa==0', {
       'targets': [
         {
           'target_name': 'khronos_headers',
           'type': 'none',
           'all_dependent_settings': {
             'include_dirs': [
               '.',
               '../../gpu',  # Contains GLES2/gl2chromium.h
             ],
           },
         },
       ],
-    }, { # use_system_khronos==1
+    }, { # use_system_mesa==1
       'targets': [
         {
           'target_name': 'khronos_headers',
           'type': 'none',
           'variables': {
             'headers_root_path': '../..',
             'header_filenames': [
               'GLES2/gl2.h;<GLES2/gl2chromium.h>;',
               'GLES2/gl2ext.h;<GLES2/gl2chromium.h>;<GLES2/gl2extchromium.h>',
             ],
             'shim_generator_additional_args': [
               '--headers-root', '.',
               '--use-include-next',
             ],
+            'khronos_headers_symlink_source%': '/usr/include',
+            'khronos_headers_symlink_target': '<(SHARED_INTERMEDIATE_DIR)/khronos_symlinks',
           },
           'includes': [
             '../../build/shim_headers.gypi',
           ],
           'all_dependent_settings': {
             'include_dirs': [
+              '<(khronos_headers_symlink_target)',
               '../../gpu',  # Contains GLES2/gl2chromium.h
             ],
           },
+          'actions': [
+            # Symlink system headers into include paths so that nacl
+            # untrusted build can use them. Adding system include paths
+            # to nacl untrusted build include path would break the build,
+            # so we only add needed parts.
+            {
+              'action_name': 'create_khronos_symlinks_gles2',
+              'variables': {
+                'dummy_file':  '<(khronos_headers_symlink_target)/.dummy_gles2',
+              },
+              'inputs': [
+                'khronos.gyp',
+              ],
+              'outputs': [
+                '<(dummy_file)',
+              ],
+              'action': [
+                '../../build/symlink.py',
+                '--force',
+                '--touch', '<(dummy_file)',
+                '<(khronos_headers_symlink_source)/GLES2',
+                '<(khronos_headers_symlink_target)',
+              ],
+              'message': 'Creating GLES2 headers symlinks.',
+            },
+            {
+              'action_name': 'create_khronos_symlinks_khr',
+              'variables': {
+                'dummy_file':  '<(khronos_headers_symlink_target)/.dummy_khr',
+              },
+              'inputs': [
+                'khronos.gyp',
+              ],
+              'outputs': [
+                '<(dummy_file)',
+              ],
+              'action': [
+                '../../build/symlink.py',
+                '--force',
+                '--touch', '<(dummy_file)',
+                '<(khronos_headers_symlink_source)/KHR',
+                '<(khronos_headers_symlink_target)',
+              ],
+              'message': 'Creating KHR headers symlinks.',
+            },
+          ],
         },
       ],
     }],
   ],
 }