Update gcmole to a more recent clang/llvm.

* Changes for 2.9:
     * Use CXX in Makefile instead of hardwired g++, we need a more
       modern GCC than 4.6 later, anyway.

* Changes for 3.0:
     * Use llvm namespace.
     * Diagnostic => DiagnosticsEngine.

* Changes for 3.1:
     * The BlockDeclRefExpr AST node is gone.
     * The structure of the CXXNewExpr AST node has changed.
     * Path changed from Release to Release+Asserts.
     * Use clang++ instead of -cc1, otherwise we lose the system include
       paths.

* Changes for 3.2:
     none needed

* Changes for 3.3:
     * Use lookup_iterator::begin/end instead of first/second.

* Changes for 3.4:
     * createItaniumMangleContext => ItaniumMangleContext::create.

* Changes for 3.5:
     * clang uses <type_traits> now, so -std=c++0x is needed.
     * Type-trait-related AST changes.
     * getCustomDiagID signature changed.
     * We must link the C++ library statically now.

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/445983002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22972 ce2b1a6d-e550-0410-aec6-3dcde31c8c00