[PATCH] Avoid definining more GCC specific predefined macros in clang-cl

[João Matos]

>>! In D4419#6, @ehsan wrote:
> So which flag should I use instead?  Honestly these different flags confuse me and I'm not sure which one is supposed to be used for which purpose.

Maybe you can use the "msvc" environment part of the triple for this.

http://reviews.llvm.org/D4419