Reorganize predefined macros for all Windows targets.

This adds an option to set the _MSC_VER macro without
recompiling. This is very useful when testing compatibility
with the Windows SDK and c++stdlib headers.

-fmsc-version=<version> (defaults to VS2003 (1300))

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@116999 91177308-0d34-0410-b5e6-96231b3b80d8
10 files changed