"Blink" in ordinary C?

and how every you want to dress it up Arduino code is not C

Arduino code is very much C. The only thing the IDE does other than pass sketches directly to a compiler is to patch up some of the more opaque requirements for forward reference function prototypes... And there's a little bit of C++.

Now, the arduino core library functions are not the same as desktop library functions. But then they couldn't be...