Fix compile error on Mac.

src/spaces.cc

 // Copyright 2011 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 265 matching lines @@
 
   memory_allocator_reserved_ = 0;
   size_executable_ = 0;
 
   return true;
 }
 
 
 void MemoryAllocator::TearDown() {
   // Check that spaces were torn down before MemoryAllocator.
-  CHECK_EQ(memory_allocator_reserved_, static_cast<intptr_t>(0));
+  CHECK_EQ(memory_allocator_reserved_, static_cast<size_t>(0));
   // TODO(gc) this will be true again when we fix FreeMemory.
   // ASSERT(size_executable_ == 0);
   capacity_ = 0;
   capacity_executable_ = 0;
 }
 
 
 void MemoryAllocator::FreeMemory(VirtualMemory* reservation,
                                  Executability executable) {
   // TODO(gc) make code_range part of memory allocator?
@@ skipping 2556 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal