Util: Add interface detection for FreeBSD (bug 1730)

I've also been hit with this bug on FreeBSD where
iproute2 is not available.

FreeBSD 8.2-STABLE i386

I wrote a little patch to make gpodder work on FreeBSD.
bin/gpo: Fix broken "YouTube" command
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' into njsf-m-busy-updateall