Update Clang for a minor DIBuilder breaking change.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176003 91177308-0d34-0410-b5e6-96231b3b80d8
Documentation: add an idea for a (weird) clang tool


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176005 91177308-0d34-0410-b5e6-96231b3b80d8