sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

sys: 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

sys: Remove $FreeBSD$: one-line .c pattern

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

sys/kern: 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.

ANSIfy sys/libkern

PR: 223641
Submitted by: ota@j.email.ne.jp
MFC after: 1 week

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

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

MFlibc: Remove extra closing parenthesis.

/* -> /*- for copyright notices, minor format tweaks as necessary

Use sys/libkern.h not /usr/include/string.h

Remove 'register' keyword.

rcsid[]->__FBSDID

Sync to OpenBSD (update comment and minor style change).

Obtained from: OpenBSD
MFC after: 1 week

Make the rcsid and FreeBSD IDs more sane in the wcs* and wmem* files.
Do the same for the non-wcs*/wmem* files while I'm here.

- Reverse the order of two loop invariant to ensure strlcat() does not
attempt to read memory when siz is 0
- Clarify comments referring to strlcat() usage

PR: 24278, 24295
Submitted by: Tony Finch <dot@dotat.at>
Richard Kettlewell <rjk@greenend.org.uk>
Reviewed by: -audit

Use the latest version of these files from OpenBSD.

1) Safty change from casper dik was added to OpenBSD's sources since I
grabbed them. milltert@openbsd.org
2) Split up strlcpy to improve efficiency of the common case.
milltert@openbsd.org
3) Cleanup of cross references for man page. {alex,aaron}@openbsd.org

Pointed out by: deraadt@openbsd.org

Import strl{cat,cpy} from OpenBSD.

Obtained from: OpenBSD