Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Fix a bug in bsdgrep that caused the program to hang in a tight loop for
some combinations of command line options and search patterns. The code was
examining regexec flags looking for a regcomp flag value. The fix is to
look in the struct field where the decoded regcomp flag was stored when the
regex was compiled.

With this fix, it's possible to build WITHOUT_GNU_GREP_COMPAT and
WITH_BSDGREP and have a usable GPL-free grep (which of course lacks gnugrep
extensions). It now passes the kyua tests except for one test that requires
the -z/--null-data gnu extension, and one test involving outputting context
lines across multiple files which appears to sometimes output an extra
delimiter line ("--") between matches (a rather obscure failure of a rather
obscure feature, so bsdgrep should be generally usable now).

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: delphij (mentor)
Sposored by: Google Summer of Code 2011
MFC after: 1 week