git: network.subr: Add ipv6if()

[Aaron LI]

commit da4dd5142b3aeee28a624360613a09cc38ec7319
Author: Aaron LI <***@aaronly.me>
Date: Fri Oct 26 01:05:20 2018 +0800

network.subr: Add ipv6if()

This function determines whether the given interface should be
configured for IPv6. This function will be used to determine whether to
apply DHCPv6 to an interface in the following commit.

Taken from FreeBSD, but modified to consider ${ipv6_enable}.

Summary of changes:
etc/network.subr | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/da4dd5142b3aeee28a624360613a09cc38ec7319