xdr_setpos(3) on FreeBSD

The text 55f700b2edf5, as FreeBSD 2.2.8-RELEASE, FreeBSD 2.2.7-RELEASE, FreeBSD 2.2.6-RELEASE, FreeBSD 2.2.5-RELEASE, FreeBSD 2.2.2-RELEASE shipped it.

library routines for external data representation

xdr_setpos(3) on FreeBSD now