Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

resizewin: Stop printing bogus NUL to TTY

A char array has an implicit NUL terminating it, which sizeof will
include, so we need to subtract 1 here. Printing a NUL can cause issues
for things like CI environments that aren't expecting it, especially
with recent Jenkins being stricter about not putting NUL in XML files.

Fixes: 3d222369acbe ("Add a small tool, resizewin(1), to query terminal for window size")
MFC after: 1 week

Improve terminology in a comment.

Suggested by: ian
MFC after: 2 weeks

Make resizewin(1) do flushing by using TCSAFLUSH instead of TCSANOW
followed by tcflush(3). This works just as well and is more elegant.

Suggested by: bde
MFC after: 2 weeks
Sponsored by: DARPA, AFRL

Sort variable declarations; no functional changes.

MFC after: 2 weeks
Sponsored by: DARPA, AFRL

Add resizewin -z. It makes resizewin not do anything if the terminal
size is already set to something other than zero. It's supposed to be
called from eg /etc/profile - it's not neccessary to query terminal
size when logging in over the network, because the protocol used already
takes care of this, but it's neccessary when logging over a serial line.

Reviewed by: cem, Daniel O'Connor <darius@dons.net.au>
MFC after: 2 weeks
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D10637

Use tcflush(3) instead of (nonstandard) TIOCFLUSH.

Reported by: kib
MFC after: 2 weeks
Sponsored by: DARPA, AFRL

Make resizewin(1) discard the terminal queues, to lower the chance
for "unable to parse response" error which happens when youre typing
too fast for the machine you're running it on.

Reviewed by: cem, Daniel O'Connor <darius@dons.net.au>
MFC after: 2 weeks
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D10624

Rename a variable, hopefully fixing build after r317901.

MFC after: 2 weeks
Sponsored by: DARPA, AFRL

Improve error reporting in resizewin(1).

Reviewed by: cem (earlier version)
MFC after: 2 weeks
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D10624

Add a small tool, resizewin(1), to query terminal for window size

Submitted by: Daniel O'Connor
Reviewed by: kan, wblock, cem
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D4438