Summary:
This fixes PR17145 and avoids unknown pragma warnings.
This change does not attempt to map MSVC warning numbers to clang
warning flags. Perhaps in the future we will implement a mapping for
some common subset of Microsoft warnings, but for now we don't.
Reviewers: rsmith
CC: cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1652
llvm-svn: 190726