Make not sucking at regexp the default...

src/x64/regexp-macro-assembler-x64.h

 // Copyright 2009 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
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 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef V8_X64_REGEXP_MACRO_ASSEMBLER_X64_H_
 #define V8_X64_REGEXP_MACRO_ASSEMBLER_X64_H_
 
 namespace v8 {
 namespace internal {
 
-#ifdef V8_NATIVE_REGEXP
+#ifndef V8_INTERPRETED_REGEXP
 
 class RegExpMacroAssemblerX64: public NativeRegExpMacroAssembler {
  public:
   RegExpMacroAssemblerX64(Mode mode, int registers_to_save);
   virtual ~RegExpMacroAssemblerX64();
   virtual int stack_limit_slack();
   virtual void AdvanceCurrentPosition(int by);
   virtual void AdvanceRegister(int reg, int by);
   virtual void Backtrack();
   virtual void Bind(Label* label);
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   // Labels used internally.
   Label entry_label_;
   Label start_label_;
   Label success_label_;
   Label backtrack_label_;
   Label exit_label_;
   Label check_preempt_label_;
   Label stack_overflow_label_;
 };
 
-#endif  // V8_NATIVE_REGEXP
+#endif  // V8_INTERPRETED_REGEXP
 
 }}  // namespace v8::internal
 
 #endif  // V8_X64_REGEXP_MACRO_ASSEMBLER_X64_H_