Hello, how does
	ftp://ftp.netbsd.org/pub/NetBSD/packages/pkgsrc/README-IPv6.html
	detect IPv6-ready pkgsrc?  I wonder why net/bind9 is considered as
	IPv6-ready package, while it has no BUILD_DEFS+=USE_INET6.  What is
	the right way to write Makefile for:
	- pkgsrc that are not IPv6 ready
	- pkgsrc that are always IPv6 ready
	- pkgsrc that autodetects IPv6 readiness

itojun