[PATCH] D14180: enable -fms-extensions by default on the mingw-w64 target

[Martell Malone via cfe-commits]

martell added a comment.

> This is what I'm worried about. :) Can you elaborate on what would break?


Essentially mingw-w64 has a few header defines for working around builtings such as __rtdsc and the interlocked functions and some other builtins
As soon as one of these headers are included it would result in a compile time error as it would collide with what clang now provides.

I have talked to jon_y the 4.x maintainer about this before.
We could port back my patches to next 4.x release which i believe is 4.0.4.
But essentially older versions of mingw-w64 that doesn't respect the compiler may have the builtins would not work.

We don't have to make this break now of course but we should do it at some point?


http://reviews.llvm.org/D14180