Create the clang++ symlink as a POST_BUILD custom command on clang.

This saves us from re-creating the symlink on every build even if we
didn't rebuild clang.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@145017 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed