[Isolates] Fix build on 64-bit version of Windows with vs2008

SConstruct

 # Copyright 2010 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 559 matching lines @@
         },
       },
       'pgo:instrument': {
         'LINKFLAGS':    ['/LTCG:PGI']
       },
       'pgo:optimize': {
         'LINKFLAGS':    ['/LTCG:PGO']
       }
     },
     'arch:ia32': {
-      'CPPDEFINES': ['V8_TARGET_ARCH_IA32'],
+      'CPPDEFINES': ['V8_TARGET_ARCH_IA32', 'WIN32'],
       'LINKFLAGS': ['/MACHINE:X86']
     },
     'arch:x64': {
       'CPPDEFINES': ['V8_TARGET_ARCH_X64'],
       'LINKFLAGS': ['/MACHINE:X64', '/STACK:2091752']
     },
     'mode:debug': {
       'CCFLAGS':    ['/Od'],
       'LINKFLAGS':  ['/DEBUG'],
       'CPPDEFINES': ['DEBUG'],
@@ skipping 592 matching lines @@
 # version of scons.  Also, there's a bug in some revisions that
 # doesn't allow this flag to be set, so we swallow any exceptions.
 # Lovely.
 try:
   SetOption('warn', 'no-deprecated')
 except:
   pass
 
 
 Build()