fix erroring out on win x64 due to bad compiler version check

base/win/win_util.cc

 // 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.
 
 #include "base/win/win_util.h"
 
 #include <aclapi.h>
 #include <shellapi.h>
 #include <shlobj.h>
 #include <shobjidl.h>  // Must be before propkey.
@@ skipping 314 matching lines @@
     return true;
   }
   return false;
 }
 
 }  // namespace win
 }  // namespace base
 
 #ifdef _MSC_VER
 
-// There are optimizer bugs in VS2012 pre-Update 1.
-#if _MSC_VER == 1700 && _MSC_FULL_VER < 170051106
+// There are optimizer bugs in x86 VS2012 pre-Update 1.
+#if _MSC_VER == 1700 && defined _M_IX86 && _MSC_FULL_VER < 170051106
 #error Must install Update 1 to Visual Studio 2012.
 #endif
 
 #endif  // _MSC_VER
 
 #ifndef COPY_FILE_COPY_SYMLINK
 #error You must install the Windows 2008 or Vista Software Development Kit and \
 set it as your default include path to build this library. You can grab it by \
 searching for "download windows sdk 2008" in your favorite web search engine.  \
 Also make sure you register the SDK with Visual Studio, by selecting \
 "Integrate Windows SDK with Visual Studio 2005" from the Windows SDK \
 menu (see Start - All Programs - Microsoft Windows SDK - \
 Visual Studio Registration).
 #endif