Comment by jstimpfle

I don't know about you but I need zero POSIX to write C on Windows. Not even much of the (mostly bad) C standard library. I use snprintf for convenience (but I don't have to), and memcpy, that's about it.

And many projects properly abstract their OS layer so they aren't tied to POSIX.

Maybe Unix is tied to C, but C isn't tied to Unix.