Share the zygote's fopen overrides with nacl_helper.

chrome/nacl.gypi

 # 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.
 
 {
   'include': [
     '../native_client/build/untrusted.gypi',
   ],
   'target_defaults': {
     'variables': {
@@ skipping 131 matching lines @@
               'dependencies': [
                 '../crypto/crypto.gyp:crypto',
                 'nacl',
               ],
               'sources': [
                 'nacl/nacl_helper_linux.cc',
                 '../base/posix/unix_domain_socket.cc',
                 '../chrome/common/nacl_messages.cc',
                 '../chrome/common/nacl_types.cc',
                 '../content/common/child_process_sandbox_support_impl_shm_linux.cc',
+                '../content/zygote/zygote_libc_override_linux.cc',
+                '../content/zygote/zygote_libc_override_linux.h',
               ],
               'conditions': [
                 ['toolkit_uses_gtk == 1', {
                   'dependencies': [
                     '../build/linux/system.gyp:gtk',
                   ],
                 }],
                 ['use_glib == 1', {
                   'dependencies': [
                     '../build/linux/system.gyp:glib',
@@ skipping 32 matching lines @@
               'target_name': 'nacl_win64',
               'type': 'none',
               'sources': [],
             },
           ],
         }],
       ],
     }],
   ],
 }