Audit library for macro usage

[phillipjohnston]

Per the C standard:

"unless explicitly stated otherwise in the detailed descriptions [...] For the same syntactic reason, it is permitted to take the address of a library function even if it is also defined as a macro"

The related footnote states:

185. This means that an implementation shall provide an actual function for each library function, even if it also provides a macro for that function.

Should audit library usage to make sure this is followed.