In message <9055.955717215@coconut.itojun.org>itojun@iijlab.net writes
>
>>INET6 is defined unconditionally by the inclusion of
>>basesrc/lib/libwrap/Makefile.cflags
>>INET6 and NETISO (!!!) are both defined unconditionally
>>by the inclusion of gnusrc/gnu/usr.sbin/sendmail/Makefile.inc
>
>	we define them unconditionally to help people who gets binary
>	distribution happy.  basically, binaries are designed to be
>	"protocol independent" - works fine on IPv4-only kernel, IPv4/v6
>	kernel and IPv6-only kernel.
>
>	if we make them conditional, binary builds will become complicated
>	too much (and impose pain to users).


And forcing users to carry around IPv6, even if they don't want to,
_doesn't_ cause them pain?  :-)