Bugfix: Several problems with the wrapping define macros, unused private functions...

Bugfix: Several problems with the wrapping define macros, unused private functions, and non-existent functions.

The stand alone builds revealed several problems with the wrapping define macros.
The ones that I noticed or were blocking me from compiling have been fixed.
It will be no surprise if there are still more such problems hiding in the code somewhere.

Remove stale and unused private functions.

There is are no f_file_clone_at() and f_file_copy_at() functions.
Remove references and related wrapping define macros.