Remove copyright strings ifdef'd out

We've ifdef'd out the copyright strings for some time now. Go ahead and
remove the ifdefs. Plus whatever other detritis was left over from other
recent removals. These copyright strings are present in the comments and
are largely from CSRG's attempt at adding their copyright to every
binary file (which modern interpretations of the license doesn't
require).

Sponsored by: Netflix

libexec: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

Remove $FreeBSD$: one-line .c pattern

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

Mark usage function as __dead2 in programs where it does not return

In most cases, usage does not return, so mark them as __dead2. For the
cases where they do return, they have not been marked __dead2.

Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/735

rbootd: Remove an unnecessary (and incomplete) function prototype.

Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D39522

General further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

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.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

Remove the 3rd clause ("advertising clause") of the BSD license as
permitted by the University of Berkeley on July 22, 1999.

Reviewed by: imp
MFC after: 1 week

Rework all non-contributed files that use `struct timezone'.

This structure is not part of POSIX. According to POSIX, gettimeofday()
has the following prototype:

int gettimeofday(struct timeval *restrict tp, void *restrict tzp);

Also, POSIX states that gettimeofday() shall return 0 (as long as tzp is
not used). Remove dead error handling code. Also use NULL for a
nul-pointer instead of integer 0.

While there, change all pieces of code that only use tv_sec to use
time(3), as this provides less overhead.

Spelling fixes for libexec/

Add __unused

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

- Import the HEAD csup code which is the basis for the cvsmode work.

Avoid accidental use of ANSI C trigraphs.

Spotted by: Pawel Worach
Obtained from: NetBSD (rev. 1.11, 1.13)

o __P removal
o register removal
o use new style prototypes and function definitions

Format string paranoia

Obtained from: OpenBSD

$Id$ -> $FreeBSD$

Ensure that things returned by gethostname() and
friends are terminated and allow for a maximum
host name length of MAXHOSTNAMELEN - 1.
Put parenthesis around sizeof args.
Make some variables static.
Fix telnetd -u (broken by my last commit)

Prompted by: bde

Add usage(), rcsids.

Import Lite2's src/libexec, except for makekey (which was spammed
by a repository copy from 1.1.5 and patched back to Lite1) and
rbootd/bootdir/SYSHPBSD (which is binary). All changed files have
already left the vendor branch.

Zap register keyword usage and convert: bcopy -> memmove, bzero -> memset,
index -> strchr, and rindex -> strrchr.

Merge conflicts and make this compile -Wall clean.

Import of NetBSD's rbootd version 19970629

compare return value from getopt against -1 rather than EOF, per the final
posix standard on the topic.

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.

add forgotten $Id$

Remove trailing whitespace.

BSD 4.4 Lite Libexec Sources