Remove $FreeBSD$: two-line nroff pattern

Remove /^\.\\"\n\.\\"\s*\$FreeBSD\$$\n/

etcupdate: Add a -N flag to perform a NO_ROOT build

This is in preparation for including an etcupdate tree when performing a
-DNO_ROOT release image build. Although -DNO_ROOT can be passed via -M,
to be useful we need to mangle the resulting METALOG to mirror the
various cleanups to the tree that are done after the build (removing
generated files, empty files and empty directories), so etcupdate needs
its own flag.

Reviewed by: jhb, pauamma
Obtained from: CheriBSD
Differential Revision: https://reviews.freebsd.org/D35857

etcupdate: Add a -m flag to change the make binary that's run

This will allow release/Makefile to forward on ${MAKE} to allow building
on non-FreeBSD systems where ${MAKE} is something other than make, as
make is typically GNU make in such situations.

Reviewed by: jhb, pauamma
Obtained from: CheriBSD
Differential Revision: https://reviews.freebsd.org/D35854

etcupdate: Add -D destdir to usage for 'extract'.

Reported by: Mark Millard <marklmi@yahoo.com>
MFC after: 1 week

etcupdate: Add a revert mode to restore one or more stock files.

Reviewed by: imp
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D29846

Cross-reference mergemaster(8) & etcupdate(8).

Suggested by: Daniel Ebdrup
Reviewed by: bcr
Approved by: bcr (doc), krion (mentor, implicit), mat (mentor, implicit)
Differential Revision: https://reviews.freebsd.org/D18350

Remove redundant word.

Reviewed by: bjk, bcr
Differential Revision: https://reviews.freebsd.org/D6064

tzsetup(1) -> tzsetup(8)

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Document the post-merge actions of calling tzsetup(8) and services_mkdb(8)
added in r259134.

MFC after: 3 days

Reassign copyright statements on several files from Advanced
Computing Technologies LLC to Hudson River Trading LLC.

Approved by: Hudson River Trading LLC (who owns ACT LLC)
MFC after: 1 week

Rework the EXAMPLES section to be a bit clearer.
- Add an example of using etcupdate diff.
- Create a subsection on bootstrapping that is below the simple
examples. This should make it clearer that 'etcupdate extract' is
a one-time operation and not part of the common workflow. It also
adds more suggestions on when bootstrapping is needed and additional
steps to make future merges simpler.

Reviewed by: adrian
MFC after: 3 days

use .Mt to mark up email addresses consistently (part2)

PR: 191174
Submitted by: Franco Fichtner <franco@lastsummer.de>

- Refresh /etc/localtime after each update using tzsetup -r.
- Regenerate /var/db/services.db when /etc/services changes.

MFC after: 1 week

Add a pre-world mode of updating similar to the -p option that can be
passed to mergemaster. In this mode, only changes to /etc/master.passwd
and /etc/group are merged to /etc. In addition, it uses a temporary
tree to stage these changes rather than overwriting the existing
'current' and 'previous' trees so that a full update can be run after
a normal installworld has completed.

MFC after: 2 weeks

Sort option flags and fix the width of the options list. This is a purely
mechanical change, no content changes.

Add HISTORY section.

Minor mdoc, spelling and end of line whitespace fixes.

The etcupdate utility is a tool for managing updates to files that are
not updated as part of `make installworld' such as files in /etc. It
manages updates by doing a three-way merge of changes made to these files
against the local versions. It is also designed to minimize the amount
of user intervention with the goal of simplifying upgrades for clusters
of machines.

The primary difference from mergemaster is that etcupdate requires less
manual work. The primary difference from etcmerge is that etcupdate
updates files in-place similar to mergemaster rather than building a
separate /etc tree.

Requested by: obrien, kib, theraven, joeld (among others)