Move version macros to public V8 header.

include/v8config.h

 // Copyright 2013 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 426 matching lines @@
 #elif V8_HAS___ALIGNOF__
 # define V8_ALIGNOF(type) __alignof__(type)
 #else
 // Note that alignment of a type within a struct can be less than the
 // alignment of the type stand-alone (because of ancient ABIs), so this
 // should only be used as a last resort.
 namespace v8 { template <typename T> class AlignOfHelper { char c; T t; }; }
 # define V8_ALIGNOF(type) (sizeof(::v8::AlignOfHelper<type>) - sizeof(type))
 #endif
 
+
+// This macro accepts another macro or a string and converts it into a string
+// after preprocessor argument expansion.
+// Use like:
+//  #define AGE 42
+//  const gchar* greeting = V8_STRINGIFY(AGE) " today!";
+#define V8_STRINGIFY(macro_or_string) V8_STRINGIFY_ARG(macro_or_string)
+#define V8_STRINGIFY_ARG(contents)    #contents
+
 #endif  // V8CONFIG_H_