PR15956: Debug Info: Include the appropriate file location in types created due to using declarations

We might benefit from API refactoring here (why pass in a value that's
derived from another parameter?) but this is the immediate issue.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181747 91177308-0d34-0410-b5e6-96231b3b80d8
Use atomic instructions on linux thumb v7.

This matches gcc's behaviour. The patch also explicitly parses the version so
that this keeps working when we add support for v8.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181750 91177308-0d34-0410-b5e6-96231b3b80d8