Unfortunately, Microsoft has stated publicly on a few occasions that they have no plans of supporting C99 or C11 outside of what they have to implement anyway for new versions of C++.

The article isn't very clear, but I would guess backward compatibility is going to trump adding new features as far as the C compiler goes.

I wouldn't mind getting proved wrong, but the article mentions a lot of C++ features they're working on, and doesn't mention an C features they're working on.