Hide pthread cancellation routines behind #ifdef NOT_YET.  They are not currently supported.  Also corrected the declaration for pthread_testcancel which incorrectly returned int when POSIX and SUSv2 both say it should be void.
Hide pthread cancellation routines behind #ifdef NOT_YET.  They are
not currently supported.  Also corrected the declaration for
pthread_testcancel which incorrectly returned int when POSIX and
SUSv2 both say it should be void.

Submitted by:	Ralf S. Engelschall <rse@engelschall.com>
Reviewed by:	John Birrell <jb@freebsd.org>

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase