BSD grep from FreeBSD for Linux.
Imported from freebsd-src, commit d1c965f (26 Dec 2020); this will be the
default grep in the upcoming FreeBSD 13 release:
Switch to the BSDL grep implementation now that it's been a little more thoroughly tested and theoretically supports all of the extensions that gnugrep in base had with our libregex(3).
Folks shouldn't really notice much from this update; bsdgrep is slower than gnugrep, but this is currently the price to pay for fewer bugs. Those dissatisfied with the speed of grep and in need of a faster implementation should check out what textproc/ripgrep and textproc/the_silver_searcher can do for them.
Run update.sh to update the sources, and use the standard make and make install to install it.
TODO: port the tests as well.