We know exactly what the value of $< is, so instead of using `basename $<` to

We know exactly what the value of $< is, so instead of using `basename $<` to
get just the filename and not the full path, just use the filename directly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9730 91177308-0d34-0410-b5e6-96231b3b80d8