Move GL headers from gpu to third_party/khronos

ppapi/native_client/src/shared/ppapi_proxy/nacl.scons

 # -*- python -*-
 # Copyright (c) 2011 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.
 
 Import('env')
 
 # Underlay $SOURCE_ROOT/gpu in this directory.
 Dir('.').addRepository(Dir('#/../gpu'))
 
 # To enable getting the generated include files and sources and also common and
 # client GPU command buffer sources.
 env.Append(CPPPATH=
           ['${SOURCE_ROOT}/native_client/src/shared/ppapi_proxy/untrusted',
-           '$SOURCE_ROOT/gpu'])
+           '$SOURCE_ROOT/third_party/khronos', '$SOURCE_ROOT/gpu'])
 
 env.Append(CPPDEFINES=['XP_UNIX'])
 env.FilterOut(CCFLAGS=['-Wswitch-enum'])
 env.Append(CCFLAGS=['-Wno-long-long'])
 
 # The PPAPI RPCs are specified abstractly via .srpc files.
 # Once a .srpc file is added to the UntrustedSrpc rules below, the low-level
 # server/client proxies and stubs can be generated automatically using
 #   scons srpcgen
 # The .cc files are written to ./ and .h files - to ./untrusted/srpcgen/.
@@ skipping 149 matching lines @@
          'srpc',
          'gio',
          'platform',
         ])
 
 header_install = env.AddHeaderToSdk(['ppruntime.h'])
 env.AddLibraryToSdk(libppruntime)
 
 # Clients that overload main() will use ppruntime.h.
 env.Requires(libppruntime, header_install)