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

usr.bin: 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 $FreeBSD$: two-line .c pattern

Remove /^#include\s+<sys/cdefs.h>.*$\n\s+__FBSDID\("\$FreeBSD\$"\);\n/

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.

Renumber copyright clause 4

Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96

Fix a ton of speelling errors

arc lint is helpful

Reviewed By: allanjude, wblock, #manpages, chris@bsdjunk.com
Differential Revision: https://reviews.freebsd.org/D3337

Fix typos

Apply seom style(9) fixes from NetBSD

Obtained from: NetBSD

Replace homebrewed NIL by NULL

Use stdbool instead of homebrewed boolean

Ansify to allow to work on it later

Remove the advertising clause from UCB copyrighted files in usr.bin. This
is in accordance with the information provided at
ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change

Also add $FreeBSD$ to a few files to keep svn happy.

Discussed with: imp, rwatson

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.

remove __P

WARNS=2 fix, kill register keyword, use __FBSDID().

NO_WERROR set because of hard-to-fix warnings originating in
system headers.

Change the name of a variable from _start to s_start. On alpha there
must be a library function called _start.

Slightly improve the C and C++ support. Allow for function return
types being on the same line as the function name, this finally closes
PR # bin/1785. Also allow :: and ~ as part of the function name, for
C++.

Still, C++ operator overloading will not be recognized as a valid
function name. Fixing this would require a major overhaul of the \p
recognition parser.

Some cleanup:

. correct a typo in regexp.c,
. implement a new "nc" (non-comment) feature to describe exceptions from
the comment detection; there were problems in Perl with the $# operator
that could not be solved by any other means,
. prevent blocklevel from becoming negative (due to earlier misdetected
sequences), this is probably a workaround for the problem described
in PR # bin/1785,
. update the Perl description to use the "nc" feature,
. update the man page for the "nc" and the undocumented "ab"/"ae"
features.

Remove trailing whitespace.

BSD 4.4 Lite Usr.bin Sources