Prepare for using ninja for win64.

build/standalone.gypi

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 340 matching lines @@
       },
       'Optdebug': {
         'inherit_from': [ 'DebugBaseCommon', 'DebugBase1' ],
       },
       'Debug': {
         # Xcode insists on this empty entry.
       },
       'Release': {
         'cflags+': ['<@(release_extra_cflags)'],
       },
+      'conditions': [
+        ['OS=="win"', {
+          'Optdebug_x64': {
+            'inherit_from': ['Optdebug'],
+          },
+          'Debug_x64': {
+            'inherit_from': ['Debug'],
+          },
+          'Release_x64': {
+            'inherit_from': ['Release'],
+          },
+        }],
+      ],
     },
     'conditions':[
       ['(clang==1 or host_clang==1) and OS!="win"', {
         # This is here so that all files get recompiled after a clang roll and
         # when turning clang on or off.
         # (defines are passed via the command line, and build systems rebuild
         # things when their commandline changes). Nothing should ever read this
         # define.
         'defines': ['CR_CLANG_REVISION=<!(<(DEPTH)/tools/clang/scripts/update.sh --print-revision)'],
         'cflags+': [
@@ skipping 671 matching lines @@
     ['use_goma==1 and ("<(GENERATOR)"=="ninja" or clang==1)', {
       'make_global_settings': [
        ['CC_wrapper', '<(gomadir)/gomacc'],
        ['CXX_wrapper', '<(gomadir)/gomacc'],
        ['CC.host_wrapper', '<(gomadir)/gomacc'],
        ['CXX.host_wrapper', '<(gomadir)/gomacc'],
       ],
     }],
   ],
 }