Do not include FastMalloc.h in config.h.

Source/wtf/FastMalloc.h

 /*
  *  Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Library General Public
  *  License as published by the Free Software Foundation; either
  *  version 2 of the License, or (at your option) any later version.
  *
  *  This library is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  *  Library General Public License for more details.
  *
  *  You should have received a copy of the GNU Library General Public License
  *  along with this library; see the file COPYING.LIB.  If not, write to
  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  *  Boston, MA 02110-1301, USA.
  *
  */
 
 #ifndef WTF_FastMalloc_h
 #define WTF_FastMalloc_h
 
 #include "wtf/WTFExport.h"
-#include <cstddef>
 
 namespace WTF {
 
 // Initialization is implicit on first use.
 WTF_EXPORT void fastMallocShutdown();
 
 // These functions crash safely if an allocation fails.
 WTF_EXPORT void* fastMalloc(size_t);
 WTF_EXPORT void* fastZeroedMalloc(size_t);
 WTF_EXPORT void* fastRealloc(void*, size_t);
@@ skipping 10 matching lines @@
 
 } // namespace WTF
 
 using WTF::fastFree;
 using WTF::fastMalloc;
 using WTF::fastRealloc;
 using WTF::fastStrDup;
 using WTF::fastZeroedMalloc;
 
 #endif /* WTF_FastMalloc_h */