rpc_gss_oid_to_mech(3) on FreeBSD

The text a3892cce91db, as FreeBSD 13.5-RELEASE, FreeBSD 13.4-RELEASE, FreeBSD 13.3-RELEASE shipped it.

Convert a mechanism name to a GSS-API oid

rpc_gss_oid_to_mech(3) on FreeBSD now