Allow HAVE_ACCESSIBILITY to be turned off at build time

third_party/WebKit/JavaScriptCore/wtf/Platform.h

 /*
  * Copyright (C) 2006 Apple Computer, Inc.  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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 249 matching lines @@
 
 #if PLATFORM(WIN)
 #define WTF_USE_WININET 1
 #endif
 
 #if PLATFORM(WX)
 #define WTF_USE_CURL 1
 #define WTF_USE_PTHREADS 1
 #endif
 
+// allow build settings to override HAVE_ACCESSIBILITY
+#if !defined(HAVE_ACCESSIBILITY)
 #if PLATFORM(MAC) || PLATFORM(WIN) || PLATFORM(GTK)
 #define HAVE_ACCESSIBILITY 1
 #endif
+#endif
 
 #if COMPILER(GCC)
 #define HAVE_COMPUTED_GOTO 1
 #endif
 
 #if PLATFORM(DARWIN)
 
 #define HAVE_ERRNO_H 1
 #define HAVE_MMAP 1
 #define HAVE_MERGESORT 1
@@ skipping 50 matching lines @@
 
 #if !defined(ENABLE_DASHBOARD_SUPPORT)
 #define ENABLE_DASHBOARD_SUPPORT 0
 #endif
 
 #if !defined(ENABLE_SAMPLING_TOOL)
 #define ENABLE_SAMPLING_TOOL 0
 #endif
 
 #endif /* WTF_Platform_h */