[flohofwoe]

The Microsoft C compiler actually has pretty good C99 support since VS2015 (e.g. inline is definitely supported).

AFAIK the only non-supported C99 features in the C compiler are VLAs (optional since C11 anyway), and type-generic macros (those would be good to have though).

Of course it would be nice if Microsoft gave the C compiler a bit more love, especially since it's much less work keeping a C compiler uptodate than a C++ compiler, but at least we got "most of C99".