nslookups in a non-blocking manner. The adns distribution also comes with
some utilities similar to dig, host, nslookup, etc.
The port that I'm importing rips out the ${PORTOBJFORMAT} checking and
also trims the extra stuff in pkg/DESCR, which the original submission
contained.
PR: 17510
Submitted by: Kostya Lukin <lukin@sapa.ivcme.elektra.ru>
Reviewed by: billf, mharo
