Makefile: Switch Clang Makefiles to always include the top-level Clang Makefile.
 - This eliminates most dependencies on how Clang is installed relative to LLVM.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@105637 91177308-0d34-0410-b5e6-96231b3b80d8
33 files changed