One more small cleanup, forgotten yesterday.
Reported by:	lwhsu

all: Remove all other $FreeBSD keywords.

Remove # $FreeBSD$ from Makefiles.

sysutils/firstboot-pkgs: Bootstrap and update pkg unconditionally

The background of this patch is available at:
https://lists.freebsd.org/pipermail/freebsd-cloud/2020-April/000234.html

Even a `pkg -N` success, the following `pkg install` may still fail because of
the repository version doesn't match between client and server.

Therefore, unconditionally bootstrap and update pkg at firstboot to ensure pkg
and local metadata are update-to-date.

Approved by:	cperciva (maintainer)
MFH:		2020Q2
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D24517

sysutils/firstboot-pkgs: Loop through the list installing one at a time to
handle missing pkgs in the repo.

Reviewed by:	allanjude
Approved by:	cperciva, bdrewery (implicit)

- Add NO_ARCH
- Remove always-true/false conditions after FreeBSD 9, 10.1, 10.2 EOL

Approved by:	portmgr blanket

- minor cleanup
  - options in favor of using pre
  - extract_only to drop fetch target
  - no_install to drop install target

Approved by:	cperciva

Nominate myself for the useful-use-of-cat award.

pkg detects if its stdout is a terminal and prints many 'done%' lines,
which are useful for interactive use on modern terminals, but not so
useful on a serial console; piping through cat silences these.

pkg uses "is stdin a terminal?" to decide if it's running interactively
and thereby whether it should display a progress bar during downloads.
While rc.d scripts have a terminal attached, for the common case of
unattended installation of servers, this script is not being used
interactively; so redirect stdin from /dev/null to silence the progress
bars and reduce console spew.

The -q option could be used to accomplish this, but that would also
eliminate other more useful information, such as the names and versions
of packages being installed.

Fix dumb typo: Need to check if the number of rc.d scripts has changed
between pre-package-installation and post-package-installation, not
between pre- and pre-.

If firstboot_pkgs installs a package which contains an rc.d script,
request a reboot so that any newly-installed daemons will be launched.

To prevent fallout of lowering __FreeBSD_version in releng/10.0 branch,
adjust OSVERSION evaluation in ports that specifically use '100050N'.

Approved by:	affected maintainers (implicit)
Sponsored by:	The FreeBSD Foundation

Add firstboot-pkgs:

When the system first boots, install the pkg(8) tools (if not already
installed) and packages listed in the $firstboot_pkgs_list rc.conf
variable.

Obviously, this port is not useful after a system is already running; it is
intended to be included as part of the installation or disk image building
process.