Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC r226432, r226273:
- Use getprogname() instead of __progname
- Allow disabling bzip2 support with WITHOUT_BZIP2
- Fix handling patterns that start with a dot
- Remove superfluous semicolon
- Fix counting of match limit (-m)

Approved by: re (kib), delphij (mentor, implicit)

MFC 226035, 226047:

Update BSD grep to the latest development version. It has some code
backported that was written for the TRE integration project in Google
Summer of Code 2011. This is a temporary solution until the whole
regex library is not replaced so that BSD grep development can continue
and the backported code gets some review and testing. This change only
improves scalability slightly, there is no big performance boost yet
but several minor bugs have been found and fixed.

Approved by: re (kib), delphij (mentor, implicit)
Sposored by: Google Summer of Code 2011

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

- Adjust a comment to actual behaviour
- Makefile nit
- Add more CVS/SVN keywords to make it easier to track changes from NetBSD
in case they add further improvements

Approved by: delphij (mentor)
Obtained from: The NetBSD Project

UTFize my name.

- Refactor file reading code to use pure syscalls and an internal buffer
instead of stdio. This gives BSD grep a very big performance boost,
its speed is now almost comparable to GNU grep.

Submitted by: Dimitry Andric <dimitry@andric.com>
Approved by: delphij (mentor)

- Revert strlcpy() changes to memcpy() because it's more efficient and
former may be safer but in this case it doesn't add extra
safety [1]
- Fix -w option [2]
- Fix handling of GREP_OPTIONS [3]
- Fix --line-buffered
- Make stdin input imply --line-buffered so that tail -f can be piped
to grep [4]
- Imply -h if single file is grepped, this is the GNU behaviour
- Reduce locking overhead to gain some more performance [5]
- Inline some functions to help the compiler better optimize the code
- Use shortcut for empty files [6]

PR: bin/149425 [6]
Prodded by: jilles [1]
Reported by: Alex Kozlov <spam@rm-rf.kiev.ua> [2] [3],
swell.k@gmail.com [2],
poyopoyo@puripuri.plala.or.jp [4]
Submitted by: scf [5],
Shuichi KITAGUCHI <ki@hh.iij4u.or.jp> [6]
Approved by: delphij (mentor)

Add BSD grep to the base system and make it our default grep.

Deliverables: Small and clean code (1,4 KSLOC vs GNU's 8,5 KSLOC),
lower memory usage than GNU grep, GNU compatibility,
BSD license.

TODO: Performance is somewhat behind GNU grep but it is only
significant for bigger searches. The reason is complex, the
most important factor is that GNU grep uses lots of
optimizations to improve the speed of the regex library.
First, we need a modern regex library (practically by adopting
TRE), add support for GNU-style non-standard regexes and then
reevalute the performance issues and look for bottlenecks. In
the meantime, for those, who need better performance, it is
possible to build GNU grep by setting WITH_GNU_GREP.

Approved by: delphij (mentor)
Obtained from: OpenBSD (http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/grep/),
freegrep (http://github.com/howardjp/freegrep)
Sponsored by: Google SoC 2008
Portbuild tests run by: kris, pav, erwin
Acknowledgements to: fjoe (as SoC 2008 mentor),
everyone who helped in reviewing and testing