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 r264581, r264744 (partial):

Various style(9) fixes and typos in printf and grep.

#define should be followed by a tab.

MFC r244493:
Make bsdgrep behave as gnugrep and as documented: -m should only stop
reading the specific file, not any file.

Approved by: cperciva (mentor, implicit)

MFC r245057, r245688

- Fix handling of the case when multiple patterns are specified in a single
command line argument, separated by newlines

MFC r230141 (eadler):
- Remove duplicate line from usage()

MFC r228099:
- Create links to the xz and lzma versions even if BSD grep is not the
default. Nor GNU nor liblzma in base provides such functionality so
it may be useful.

MFC r228319:
- Match GNU behavior of exit code
- Rename variable that has a different meaning now

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)

- Fix handling of environmental variables when they are set to empty string

Submitted by: ttsestt@gmail.com
Approved by: re (kib), delphij (mentor)

- Use REG_NOSUB to bypass submatch counting when not necessary. This may
yield in somewhat better performance in a few cases.

Approved by: delphij (mentor)

- 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

Revert a minor part of revision 211364:

- Imply -h if single file is grepped, this is the GNU behaviour

This is already done by code above the change and have caused a regression
since this instance of code does not check Hflag.

Reported by: davidxu
Pointy hat to: delphij

UTFize my name.

- 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)

- Some minor changes to the messages to increase usefulness of error msgs

Reviewed by: hrs (Japanese catalogs),
pluknet <pluknet at gmail dot com> (Russian catalog)
Approved by: delphij (mentor)

- Use the traditional behaviour for filename and directory name inclusion
and exclusion patterns [1]
- Some improvements on the exiting code, like replacing memcpy with
strlcpy/strcpy

Approved by: delphij (mentor)
Pointed out by: bf [1], des [1]

- Fix --color behaviour to only output color sequences if stdout is a tty
or if forced mode is specified [1]
- While here, add some alternative names for the options and make then
case-insensitive
- Fix -q and -l behaviour [2]
- Some small changes to make the code easier to review

Submitted by: swell.k@gmail.com [1],
dougb [2]
Approved by: delphij (mentor)

Fix crashes when using grep -R:

- Explicitly pre-zero memory for fts_open parameters.
- Don't test against directory patterns when we are testing direct
leaf of current directory.

While I'm there plug a few of memory leaks.

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