GNU Hurd & kFreeBSD support

From: Petr Salinger <Petr.Salinger@seznam.cz>
Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=711320
Bug-ScummVM: https://sourceforge.net/tracker/?func=detail&atid=418820&aid=3614268&group_id=37116