third_party/protobuf should build on the x86_64 architecture

third_party/protobuf/src/google/protobuf/stubs/atomicops.h

 // Protocol Buffers - Google's data interchange format
 // Copyright 2012 Google Inc.  All rights reserved.
 // http://code.google.com/p/protobuf/
 //
 // 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.
@@ skipping 46 matching lines @@
 #ifndef GOOGLE_PROTOBUF_NO_THREADSAFETY
 
 #include <google/protobuf/stubs/platform_macros.h>
 
 namespace google {
 namespace protobuf {
 namespace internal {
 
 typedef int32 Atomic32;
 #ifdef GOOGLE_PROTOBUF_ARCH_64_BIT
-// We need to be able to go between Atomic64 and AtomicWord implicitly.  This
-// means Atomic64 and AtomicWord should be the same type on 64-bit.
-#if defined(GOOGLE_PROTOBUF_OS_NACL)
-// NaCl's intptr_t is not actually 64-bits on 64-bit!
-// http://code.google.com/p/nativeclient/issues/detail?id=1162
 typedef int64 Atomic64;
-#else
-typedef intptr_t Atomic64;

[Mark Mentovai, 2012/08/21 15:22:04]

You are changing this for all platforms, but I think your patch aims to only be
scoped to Mac.

-#endif
 #endif
 
 // Use AtomicWord for a machine-sized pointer.  It will use the Atomic32 or
 // Atomic64 routines below, depending on your architecture.
 typedef intptr_t AtomicWord;
 
 // Atomically execute:
 //      result = *ptr;
 //      if (*ptr == old_value)
 //        *ptr = new_value;
@@ skipping 107 matching lines @@
 // compatible with our other Atomic* types.
 #if defined(GOOGLE_PROTOBUF_OS_APPLE)
 #include <google/protobuf/stubs/atomicops_internals_atomicword_compat.h>
 #endif
 
 #undef GOOGLE_PROTOBUF_ATOMICOPS_ERROR
 
 #endif  // GOOGLE_PROTOBUF_NO_THREADSAFETY
 
 #endif  // GOOGLE_PROTOBUF_ATOMICOPS_H_