[C++] clang HEAD 9.0.0 (https://github.com/llvm-mirror/clang.git 7490b7d8ede38d701112ea7f4c50313af18fbf53) (https://github.com/llvm-mirror/llvm.git dca684aae6c3df76f1f802848e7c273f3208f5e8)