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 $FreeBSD$: one-line .c pattern

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

pom: Fix fencepost bugs.

Under some conditions pom would report "waning" and then "full", show
higher percentages than it should, and get confused by DST. Fix.

Before:

2018.01.30: The Moon is Waxing Gibbous (97% of Full)
2018.01.31: The Moon is Waning Gibbous (100% of Full)
2018.02.01: The Moon is Full
2018.02.02: The Moon is Waning Gibbous (98% of Full)

After:

2018.01.30: The Moon is Waxing Gibbous (96% of Full)
2018.01.31: The Moon is Waxing Gibbous (99% of Full)
2018.02.01: The Moon is Full
2018.02.02: The Moon is Waning Gibbous (97% of Full)

PR: 231705
Submitted by: Andrew Gierth
Approved by: allanjude (mentor)
MFC after: 2 weeks
Differential Revision: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=231705

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

No functional change intended.

pom: Remove useless cap_rights_init

Pointy-Hat: manu

Reported by: bapt

Capsicumize pom

Since pom is the only binary that can save lives, capsicumize it to be
sure that it's safe to run it.

Reviewed by: bapt

Final step of eliminating the "games" distribution: Merge src/games
(or what's left of it, at least) into src/usr.bin.

This change will not be MFCed.

Discussed at: EuroBSDCon 2014
Committed from: EuroBSDCon 2015