Eliminate the -chained-pch flag and all of the frontend and libclang options associated with it. Chained PCH is the only way to build a PCH file that includes another PCH file

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138597 91177308-0d34-0410-b5e6-96231b3b80d8
16 files changed