Disabling AAAA dns lookups in NetBSD

[David Brownlee <abs%absd.org@localhost>]

I've seen this (or similar) asked before, but the only answer I've
seen is "rewrite the application to handle IPv6 connection failure and
retry with IPv4", which is a very laudable goal, but not suitable for
all cases.

I'm attempting to use a perl script which calls Mail::IMAPClient to
connect to google (which has both IPv4 and IPv6). Obviously NetBSD
picks up the IPv6 address first, and then fails with "No route to
host".

Tools that ship with the system understand how to handle this, but is
it reasonable for every third party tool to have to do so?

Based on previous comments I've tried setting "ip6mode=off" in rc.conf
without any apparent affect.

Short of compiling a custom kernel, how would I do one of the following?
- disable AAAA lookup
- prefer A lookup to AAAA
- disable all IPv6 activity on the system