Fix compile failure with very strict gcc warning rules on Linux....

src/variables.h

 // Copyright 2006-2008 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 65 matching lines @@
   bool Is(Kind kind) const { return kind_ == kind; }
 
   bool IsKnown() const { return !Is(UNKNOWN); }
   bool IsUnknown() const { return Is(UNKNOWN); }
   bool IsLikelySmi() const { return Is(LIKELY_SMI); }
 
   void CopyFrom(StaticType* other) {
     kind_ = other->kind_;
   }
 
-  static char* Type2String(StaticType* type);
+  static const char* Type2String(StaticType* type);
 
   // LIKELY_SMI accessors
   void SetAsLikelySmi() {
     kind_ = LIKELY_SMI;
   }
 
   void SetAsLikelySmiIfUnknown() {
     if (IsUnknown()) {
       SetAsLikelySmi();
     }
@@ skipping 86 matching lines @@
   friend class VariableProxy;
   friend class Scope;
   friend class LocalsMap;
   friend class AstBuildingParser;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_VARIABLES_H_