[PATCH] MinGW toolchain

[Yaron Keren]

  Thanks Ruben!

  By hardcoded paths I did not mean what's in the patch above which are relative-to-gcc-hardcoded, that's OK.
  I meant what's in clang trunk, absolute-hardcoded paths and versions such as c:\mingw which assumes install location.

  I fully agree with you regarding mingw.org vs -w64. If supporting mingw.org required more work than adding the several include paths I listed above I'd hesitate, but if it's trivial to support than why not. BTW, LLVM does have a mingw.org building bot.

http://reviews.llvm.org/D3420