This commit mostly adds code written by Claudio Jeker for OpenBSD to
support sysctl in the interface printing parts (-i, -I, -w). The port has
been ported to NetBSD with tiny adjustments -- of course all bugs etc.
are mine.
Also add and document a -X flag to force sysctl usage. The documentation
notes this flag may be removed at any time and its presence should not be
relied on.
Some misc. comments/#ifdef changes/code snippet moves as well.
Please note that no functionality should change as the routing and
interface printing code is still not fully supported.
Mailing list reference:
http://mail-index.netbsd.org/tech-userlevel/2009/09/09/msg002604.html
Heavily based on similar code from Claudio Jeker (at OpenBSD).
While here, fix inet/inet6 sysctl stuff commited previously to
actually work, and some other nits to make netstat more sysctl
friendly.
One step closer to losing setgid kmem on this one...