Include AvailabilityMacros.h only where it is used.

Source/wtf/Assertions.cpp

 /*
  * Copyright (C) 2003, 2006, 2007 Apple Inc.  All rights reserved.
  * Copyright (C) 2007-2009 Torch Mobile, Inc.
  * Copyright (C) 2011 University of Szeged. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 28 matching lines @@
 
 #include <stdio.h>
 #include <stdarg.h>
 #include <string.h>
 
 #if HAVE(SIGNAL_H)
 #include <signal.h>
 #endif
 
 #if USE(CF)
+#include <AvailabilityMacros.h>
 #include <CoreFoundation/CFString.h>
 #if __MAC_OS_X_VERSION_MIN_REQUIRED >= 1080
 #define WTF_USE_APPLE_SYSTEM_LOG 1
 #include <asl.h>
 #endif
 #endif // USE(CF)
 
 #if COMPILER(MSVC)
 #include <crtdbg.h>
 #endif
@@ skipping 315 matching lines @@
 
 void WTFLogAlways(const char* format, ...)
 {
     va_list args;
     va_start(args, format);
     vprintf_stderr_with_trailing_newline(format, args);
     va_end(args);
 }
 
 } // extern "C"