-current vs MKINET6=NO

[Geoff Wing <gcw%pobox.com@localhost>]

Hi,
the following files need changes to build a full tree with MKINET6=NO

	external/apache2/mDNSResponder/dist/mDNSPosix/mDNSUNP.c
	external/bsd/dhcpcd/dist/src/dhcpcd.c
	external/bsd/dhcpcd/dist/src/if-bsd.c
	external/bsd/tcpdump/bin/Makefile

mDNSUNP.c needs
	#include <netinet/in_var.h>
   for some IFF_* definitions.

dhcpd stuff needs quite a few changes to remove calls to ip6 stuff

tcpdump might be better off just including ip6 stuff unconditionally
(since it's parsing packets) rather than trying to detangle all the
ip6 stuff.  A quick eyeball didn't see any ip6 headers/libs but I didn't
check fully.

I've only done quick-and-dirty patches so not including them here, especially
given that they're all external source stuff.

Regards,
Geoff