Fix windows build.

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 406 matching lines @@
   ASSERT(space->identity() == OLD_POINTER_SPACE ||
          space->identity() == OLD_DATA_SPACE ||
          space->identity() == CODE_SPACE);
 
   int number_of_pages = space->CountTotalPages();
 
   PageIterator it(space);
   const int kMaxMaxEvacuationCandidates = 1000;
   int max_evacuation_candidates = Min(
     kMaxMaxEvacuationCandidates,
-    static_cast<int>(sqrt(number_of_pages / 2) + 1));
+    static_cast<int>(sqrt(static_cast<double)(number_of_pages / 2)) + 1));
 
   if (FLAG_stress_compaction || FLAG_always_compact) {
     max_evacuation_candidates = kMaxMaxEvacuationCandidates;
   }
 
   class Candidate {
    public:
     Candidate() : fragmentation_(0), page_(NULL) { }
     Candidate(int f, Page* p) : fragmentation_(f), page_(p) { }
 
@@ skipping 3424 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal