disable signed/unsigned mismatch warning in re2

third_party/re2/re2.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': {
   },
   'targets': [
     {
       'target_name': 're2',
@@ skipping 59 matching lines @@
         'util/utf.h',
         'util/util.h',
       ],
       'conditions': [
         ['OS=="win"', {
           'sources': [
             'mswin/stdint.h'
           ],
           'include_dirs': [
             'mswin'
-          ]
+          ],
+          'msvs_disabled_warnings': [ 4018 ],
         }]
       ]
     },
   ],
 }