Explicitly provide path to C built-in includes in libc++ builds.

third_party/libc++abi/libc++abi.gyp

 # Copyright 2013 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.
 
 {
   'targets': [
     {
       'target_name': 'libc++abi',
       'type': 'shared_library',
       'variables': {
@@ skipping 14 matching lines @@
         'trunk/src/cxa_unexpected.cpp',
         'trunk/src/cxa_vector.cpp',
         'trunk/src/cxa_virtual.cpp',
         'trunk/src/exception.cpp',
         'trunk/src/private_typeinfo.cpp',
         'trunk/src/stdexcept.cpp',
         'trunk/src/typeinfo.cpp',
       ],
       'include_dirs': [
         'trunk/include',
-        '../libc++/trunk/include'
+        '../libc++/trunk/include',
+        # TODO(earthdok): remove when http://crbug.com/337426 is fixed
+        '../llvm-build/Release+Asserts/lib/clang/3.5/include/'
       ],
       'cflags': [
         '-g', '-O3', '-fPIC',
         '-std=c++11',
         '-fstrict-aliasing',
         '-Wsign-conversion',
         '-Wshadow',
         '-Wconversion',
         '-Wunused-variable',
         '-Wmissing-field-initializers',
@@ skipping 13 matching lines @@
           ['_type!="none"', {
             'include_dirs': [
               'trunk/include',
             ],
             'cflags_cc': [
               '-nostdinc++',
             ],
             'ldflags': [
               '-L<(PRODUCT_DIR)/lib/',
             ],
+            'include_dirs': [
+              # TODO(earthdok): remove when http://crbug.com/337426 is fixed
+              '../llvm-build/Release+Asserts/lib/clang/3.5/include/'
+            ],
           }],
         ],
       },
       'cflags_cc!': [
         '-fno-rtti',
       ],
       'cflags!': [
         '-fno-exceptions',
         '-fvisibility=hidden',
       ],
       'ldflags': [
         '-nodefaultlibs',
       ],
       'ldflags!': [
         '-pthread',
       ],
       'libraries': [
         '-lrt',
         '-lc',
       ]
     },
   ]
 }