MFstable10 273998:
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.

Approved by: re (delphij)

Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC various moves of tools/regressions/ tests to the new infrastructure.

- r263220 Migrate tools/regression/sbin/ to the new tests layout.
- r263222 Add Makefile missed in r263220.
- r263226 Migrate tools/regression/{usr.bin/lastcomm,usr.sbin}/ to the new tests layout.
- r263227 Migrate most of tools/regression/usr.bin/ to the new tests layout.
- r263345 Expand tabs that sneaked in into spaces.
- r263346 Migrate tools/regression/usr.bin/make/ to the new tests layout.
- r263348 Add Makefiles missed in r263346.
- r263351 Migrate tools/regression/usr.bin/pkill/ to the new tests layout.
- r263388 Mark multi_test as requiring /usr/share/dict/words.
- r263814 Fix path to the run.pl script to let these tests run.
- r264742 Prevent building tests when bootstrapping make.

This is 'make tinderbox' clean.

MFC 258063,258064,258066,258097,258185,259134:
- Add an -s option to the regression tests that specifies a path to an
alternate etcupdate.sh script to test. This allows a non-installed
version of the script to be tested more easily.
- Add a pre-world mode of updating similar to the -p option that can be
passed to mergemaster.
- Fix a couple of issues with -F:
- Fix ALWAYS_INSTALL to take precedence over the FreeBSD ID checks.
- Fix the -F option in the case that the only upstream change is a
change in the FreeBSD ID and the local file is removed.
- Refresh /etc/localtime after each update using tzsetup -r.
- Regenerate /var/db/services.db when /etc/services changes.

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

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)