Honour 'use-external-names' in FileManager

Pass through the externally-visible names that we got from the VFS down
to FileManager, and test that this is the name showing up in __FILE__,
diagnostics, and debug information.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@202442 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "Honour 'use-external-names' in FileManager"

Revert r202442, which broke the buildbots.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@202443 91177308-0d34-0410-b5e6-96231b3b80d8
"&&&" != "&&"


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@202444 91177308-0d34-0410-b5e6-96231b3b80d8
Add -mcrbits/-mno-crbits to control the PowerPC CR-bit-tracking feature

The backend currently enables CR-bit tracking by default at -O2 and higher.
These flags allow the user to override that default.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@202453 91177308-0d34-0410-b5e6-96231b3b80d8