Cleaner way to create symlink clang++

The previous way is broken when ccache is enabled, where $(CLANG_CXX)
evaluates to "<path-to-ccache> <path-to-clang++>".

Change-Id: I696eb69f8bd46dae0fbb1b698f17a992a6f34948
(cherry picked from commit deed05694a214df5f5ba39b258cdf05c88198b00)
1 file changed