Added a naive NOLINT implementation.

Summary:
Added a naive NOLINT implementation. It doesn't care about specific
linter categories, just the "// NOLINT" on the same line as a diagnostic.

Reviewers: klimek

Reviewed By: klimek

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2896
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.
[CMake] llvm_add_library(SHARED|STATIC): Fix broken OUTPUT_NAME for *_static.