Add back support for /Gv now that gyp-win64 has VS2013

pylib/gyp/msvs_emulation.py

 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 This module helps emulate Visual Studio 2008 behavior on top of other
 build systems, primarily ninja.
 """
 
 import os
@@ skipping 421 matching lines @@
     cl('OmitFramePointers', map={'false': '-', 'true': ''}, prefix='/Oy')
     cl('EnableIntrinsicFunctions', map={'false': '-', 'true': ''}, prefix='/Oi')
     cl('FavorSizeOrSpeed', map={'1': 't', '2': 's'}, prefix='/O')
     cl('FloatingPointModel',
         map={'0': 'precise', '1': 'strict', '2': 'fast'}, prefix='/fp:',
         default='0')
     cl('WholeProgramOptimization', map={'true': '/GL'})
     cl('WarningLevel', prefix='/W')
     cl('WarnAsError', map={'true': '/WX'})
     cl('CallingConvention',
-        map={'0': 'd', '1': 'r', '2': 'z'}, prefix='/G')
+        map={'0': 'd', '1': 'r', '2': 'z', '3': 'v'}, prefix='/G')
     cl('DebugInformationFormat',
         map={'1': '7', '3': 'i', '4': 'I'}, prefix='/Z')
     cl('RuntimeTypeInfo', map={'true': '/GR', 'false': '/GR-'})
     cl('EnableFunctionLevelLinking', map={'true': '/Gy', 'false': '/Gy-'})
     cl('MinimalRebuild', map={'true': '/Gm'})
     cl('BufferSecurityCheck', map={'true': '/GS', 'false': '/GS-'})
     cl('BasicRuntimeChecks', map={'1': 's', '2': 'u', '3': '1'}, prefix='/RTC')
     cl('RuntimeLibrary',
         map={'0': 'T', '1': 'Td', '2': 'D', '3': 'Dd'}, prefix='/M')
     cl('ExceptionHandling', map={'1': 'sc','2': 'a'}, prefix='/EH')
@@ skipping 600 matching lines @@
 
   # To determine processor word size on Windows, in addition to checking
   # PROCESSOR_ARCHITECTURE (which reflects the word size of the current
   # process), it is also necessary to check PROCESSOR_ARCHITEW6432 (which
   # contains the actual word size of the system when running thru WOW64).
   if ('64' in os.environ.get('PROCESSOR_ARCHITECTURE', '') or
       '64' in os.environ.get('PROCESSOR_ARCHITEW6432', '')):
     default_variables['MSVS_OS_BITS'] = 64
   else:
     default_variables['MSVS_OS_BITS'] = 32