busybox

nslookup: implement support for SRV records

Add support for querying and parsing SRV DNS records.

function                                             old     new   delta
send_queries                                        1711    1865    +154
qtypes                                                72      80      +8

Signed-off-by: Jo-Philipp Wich <jo@mein.io>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>