Use LockFile/UnlockFile for Settings to port to Windows

client/client.gyp

 # Copyright 2014 The Crashpad Authors. All rights reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #     http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 36 matching lines @@
         'simulate_crash_mac.cc',
         'simulate_crash_mac.h',
       ],
       'conditions': [
         ['OS=="win"', {
           'link_settings': {
             'libraries': [
               '-lrpcrt4.lib',
             ],
           },
-          'sources!': [
-            # Port to Win https://code.google.com/p/crashpad/issues/detail?id=13
-            'settings.cc',
-          ],
         }],
       ],
       'direct_dependent_settings': {
         'include_dirs': [
           '..',
         ],
       },
     },
   ],
 }