usr.bin: 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

Remove $FreeBSD$: one-line .c pattern

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

ident: replace sbuf(9) with open_memstream(3)

This change makes ident only dependant on libc functions

This makes our ident(1) more portable, also the fact that we only
depend on libc which is maintained with excellent backward compatibility
means that if one day ident is removed from base, someone using FreeBSD
22 will be able to fetch ident from FreeBSD 14 to run ident against
FreeBSD 1.0 binary

MFC After: 1 week

Convert `cap_enter() < 0 && errno != ENOSYS` to `caph_enter() < 0`.

No functional change intended.

Remove "All rights reserved" from my files.

See r333391 for the rationale.

MFC after: 1 week

ident(1): Capsicumify

Preopen input file list before entering Capsicum capability mode.

Feedback by: allanjude@, bapt@, emaste@ (earlier versions)
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D7918

Rewrite scan procedure with a FSM. This improves code readability by
making clear transits between different states, and avoids bug with
handling repeated $'s.

Reviewed by: bapt
Differential Revision: https://reviews.freebsd.org/D3221

Replace GNU RCS ident with a BSD license ident

Rationale: ident(1) is useful out of RCS, lot of scripts are using ident(1) and
failing when base is built WITHOUT_RCS.

This version is:
- fully compatible with RCS 5.7 ident.
- fully compatible with RCS 5.9 ident.
- passes all ident test from GNU RCS 5.9 test suite

This version has support for: svn extension for the Keyword id (double colon and
# before last $)

Différences with GNU RCS ident:
- no long options as found in GNU RCS 5.9 (but not commented there).
- '-V' reports nothing but has been added for compatibility.

Differential Revision: https://reviews.freebsd.org/D3200
Reviewed by: pfg