Time to retire some ancient network pseudo-interfaces?

[Jason Thorpe <thorpej%me.com@localhost>]

Hey folks --

I think it's time to retire some of the ancient network pseudo-interfaces that still linger in our tree.  Specifically, strip and sl.

-- strip -- Starmode Radio IP -- this was an operation mode of the Metricom Ricochet radios back in the mid-to-late-90s.  Metricom is no longer around, and I seriously doubt anyone is using these radios anymore.  (I tossed mine in an e-recycling bin many years ago.)

-- sl -- SLIP, or Serial Line IP -- This was ancient and crufty even in the 90s, as it had been obsoleted even then by PPP over serial lines.  I think the main users of SLIP on NetBSD were folks with pc532s (you could count the number of those people on one hand) as those systems had only serial lines[*] for communicating to the outside world ([*] Well, technically, I think a few people might have had a Cabletron SCSI-to-Ethernet interface, but that only reinforces my point :-)  In any case, pc532 has been relegated to the Attic, and I think SLIP should be, as well.

Thoughts?

-- thorpej