pthread_key_create(3) on FreeBSD

The text 3ad2b303f1dc, 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.

thread-specific data key creation

pthread_key_create(3) on FreeBSD now