pthread_cleanup_pop(3) on FreeBSD

The text c26c367818b4, as FreeBSD 3.2-RELEASE, FreeBSD 3.1-RELEASE, FreeBSD 3.0-RELEASE, FreeBSD 2.2.9-RELEASE, FreeBSD 2.2.8-RELEASE shipped it.

call the first cleanup routine

pthread_cleanup_pop(3) on FreeBSD now