Don't duplicate ceiling() for every POSIX platform.

src/platform-macos.cc

 // Copyright 2012 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 61 matching lines @@
       __attribute__((weak_import));
   extern void backtrace_symbols_fd(void* const*, int, int)
       __attribute__((weak_import));
 }
 
 
 namespace v8 {
 namespace internal {
 
 
-double ceiling(double x) {
-  // Correct Mac OS X Leopard 'ceil' behavior.
-  if (-1.0 < x && x < 0.0) {
-    return -0.0;
-  } else {
-    return ceil(x);
-  }
-}
-
-
 static Mutex* limit_mutex = NULL;
 
 
 // We keep the lowest and highest addresses mapped as a quick way of
 // determining that pointers are outside the heap (used mostly in assertions
 // and verification).  The estimate is conservative, i.e., not all addresses in
 // 'allocated' space are actually allocated to our heap.  The range is
 // [lowest, highest), inclusive on the low and and exclusive on the high end.
 static void* lowest_ever_allocated = reinterpret_cast<void*>(-1);
 static void* highest_ever_allocated = reinterpret_cast<void*>(0);
@@ skipping 369 matching lines @@
   limit_mutex = CreateMutex();
 }
 
 
 void OS::TearDown() {
   delete limit_mutex;
 }
 
 
 } }  // namespace v8::internal