MFC r326276:

various: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Fix using lp(1) without the new -t option after r194171.

PR: standards/129554
Tested by: Steve Kargl
MFC after: 1 week

Add -m and -t options.

PR: 129554
Submitted by: gavin
MFC after: 3 weeks

Add a dummy -s option for SUSv2 compatibility.

PR: 17256
Reported by: Brooks Davis <brooks@one-eyed-alien.net>
Approved by: jkh (release engineer)

$Id$ -> $FreeBSD$

Revert $FreeBSD$ to $Id$

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Clean out the BUGS section/comments now that our lpr has a better
option parsing.

Remove the comment about the broken getopts(1) in our /bin/sh.

Implementing the "lp" command.

This command is required to exist in terms of compatibility with the
Posix 1003.2 specification. It actually invokes the lpr service with
the proper options.