I actually mentioned this exact problem several months ago.
I have not looked at the internet headers for 1.3 in detail
yet, but using "long" for an ipv4 address seemed to be all
over the 1.2 sources, where it needs to be unsigned 32-bit int.
If NetBSD doesn't have an inet_addr_t yet, I'll reraise the
suggestion that you really, really want one.

Apologies for not using send-pr in time :).