Make it clear that GCMole depends on Clang 2.9 currently.

tools/gcmole/gcmole.cc

 // Copyright 2011 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 569 matching lines @@
     VISIT(OverloadExpr);
     VISIT(PackExpansionExpr);
     VISIT(ParenExpr);
     VISIT(ParenListExpr);
     VISIT(PredefinedExpr);
     VISIT(ShuffleVectorExpr);
     VISIT(SizeOfPackExpr);
     VISIT(StmtExpr);
     VISIT(StringLiteral);
     VISIT(SubstNonTypeTemplateParmPackExpr);
-    VISIT(UnaryExprOrTypeTraitExpr);
     VISIT(UnaryOperator);
     VISIT(UnaryTypeTraitExpr);
     VISIT(VAArgExpr);
 #undef VISIT
 
     return ExprEffect::None();
   }
 
 #define DECL_VISIT_EXPR(type)                                           \
   ExprEffect Visit##type (clang::type* expr, const Environment& env)
@@ skipping 26 matching lines @@
   IGNORE_EXPR(IntegerLiteral);
   IGNORE_EXPR(OffsetOfExpr);
   IGNORE_EXPR(ImplicitValueInitExpr);
   IGNORE_EXPR(PackExpansionExpr);
   IGNORE_EXPR(PredefinedExpr);
   IGNORE_EXPR(ShuffleVectorExpr);
   IGNORE_EXPR(SizeOfPackExpr);
   IGNORE_EXPR(StmtExpr);
   IGNORE_EXPR(StringLiteral);
   IGNORE_EXPR(SubstNonTypeTemplateParmPackExpr);
-  IGNORE_EXPR(UnaryExprOrTypeTraitExpr);
   IGNORE_EXPR(UnaryTypeTraitExpr);
   IGNORE_EXPR(VAArgExpr);
   IGNORE_EXPR(GNUNullExpr);
   IGNORE_EXPR(OverloadExpr);
 
   DECL_VISIT_EXPR(CXXThisExpr) {
     return Use(expr, expr->getType(), THIS, env);
   }
 
   DECL_VISIT_EXPR(AbstractConditionalOperator) {
@@ skipping 633 matching lines @@
 
 
 }
 
 static clang::FrontendPluginRegistry::Add<Action<ProblemsFinder> >
 FindProblems("find-problems", "Find GC-unsafe places.");
 
 static clang::FrontendPluginRegistry::Add<
   Action<FunctionDeclarationFinder> >
 DumpCallees("dump-callees", "Dump callees for each function.");