report a fatal error. This allows us to continue processing the translation
unit. Test case to come on the clang side because we need an inline asm
diagnostics handler in place.
rdar://13446483
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180873 91177308-0d34-0410-b5e6-96231b3b80d8