Export the mq_getfd_np() symbol from librt.so, which allows to get
file descriptor for the given posix mqueue. Export the
timer_oshandle_np() symbol to get ktimer id for the given posix timer.
Requested by: Lewis Donzis <lew@perftech.com>
Reviewed by: jilles
Discussed with: kan
Sponsored by: The FreeBSD Foundation
MFC after: 1 week