pthread_once(3) on FreeBSD

The text 16e7320082d3, 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.

dynamic package initialization

pthread_once(3) on FreeBSD now