Fix the GC branch so it compiles and runs on 64 bit.

src/mark-compact.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 2525 matching lines @@
 
   p->ClearFlag(MemoryChunk::WAS_SWEPT_CONSERVATIVELY);
 
   int last_cell_index =
       Page::MarkbitsBitmap::IndexToCell(
           Page::MarkbitsBitmap::CellAlignIndex(
               p->AddressToMarkbitIndex(p->ObjectAreaEnd())));
 
   int cell_index = Page::kFirstUsedCell;
   Address free_start = p->ObjectAreaStart();
-  ASSERT(reinterpret_cast<uint32_t>(free_start) % (32 * kPointerSize) == 0);
+  ASSERT(reinterpret_cast<intptr_t>(free_start) % (32 * kPointerSize) == 0);
   Address object_address = p->ObjectAreaStart();
   int offsets[16];
 
   for (cell_index = Page::kFirstUsedCell;
        cell_index < last_cell_index;
        cell_index++, object_address += 32 * kPointerSize) {
     ASSERT((unsigned)cell_index ==
         Page::MarkbitsBitmap::IndexToCell(
             Page::MarkbitsBitmap::CellAlignIndex(
                 p->AddressToMarkbitIndex(object_address))));
@@ skipping 169 matching lines @@
 }
 
 
 void MarkCompactCollector::Initialize() {
   StaticPointersToNewGenUpdatingVisitor::Initialize();
   StaticMarkingVisitor::Initialize();
 }
 
 
 } }  // namespace v8::internal