usr.sbin: 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

usr.sbin: 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/

Fix -Wpointer-sign warnings in makefs and mkimg

Reviewed By: emaste
Differential Revision: https://reviews.freebsd.org/D27175

makefs: ANSIfy

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.

Be more precise when including headers so that we're less likely to
depend on namespace pollution and as such become more portable. This
means including headers like <sys/types.h> or <stdlib.h>, but also
making sure we include system/host headers before local headers.

While here: define ENOATTR as ENOMSG in mtree.c. There is no ENOATTR
on Linux.

With this, makefs is ready for compilation on macOS and Linux.

Spelling fixes for usr.sbin/

Small cleanups to panic() prototype.

- Let panic() use _Noreturn and __printflike() instead of GCC-specific
attributes.
- Remove prototype from ffs_subr.c and let it include ffs_extern.h.
- Forward declare struct inode to make ffs_extern.h not depend on it.

Drop the include of <ufs/ffs/ffs_extern.h> from usr.sbin/makefs/ffs/ffs_bswap.c
and usr.sbin/makefs/ffs/ffs_subr.c as they have no need of anything in that
file. No other programs or libraries include <ufs/ffs/ffs_extern.h> (nor
should they as it is totally in-kernel interfaces). For added protection
I enclosed the entire contents of <ufs/ffs/ffs_extern.h> in ifdef _KERNEL.

Feedback from: Bruce Evans and Tai-hwa Liang

Use alternative, less messy solution to avoid breakage after r223020:
put the snapdata structure between #ifdef _KERNEL guards.

Suggested by: kib

Apparently makefs needs a few more system headers to compile during
buildworld.

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.