with the contents of CMAKE_C(XX)_FLAGS too, else `llvm-config
--c(xx)flags' doesn't tell the absolute truth.
This comes from PR9603 and is based on a patch by Ryuta Suzuki!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128727 91177308-0d34-0410-b5e6-96231b3b80d8