Renaming libifc back to libifconfig in response to feedback on initial commit of this library. Sticking to 'libifconfig' (and 'ifconfig_' as function prefix) should reduce chances of namespace collisions, make it more clear what the library does, and be more in line with what existing libraries do.
Submitted by: Marie Helene Kvello-Aune <marieheleneka@gmail.com>
Differential Review: https://reviews.freebsd.org/D7742