MacOS:
* https://unix.stackexchange.com/questions/352977/
* https://unix.stackexchange.com/a/398249/5132
The very version of FreeBSD from some years ago:
% bsdgrep --version
bsdgrep (BSD grep) 2.5.1-FreeBSD
% grep --version
grep (GNU grep) 2.5.1-FreeBSD
Copyright 1988, 1992-1999, 2000, 2001 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
%
More on that:* https://unix.stackexchange.com/a/65609/5132
Kyle Evans and others on making bsdgrep into grep:
strcmp("bsdgrep (BSD grep) 2.5.1-FreeBSD", "grep (GNU grep) 2.5.1-FreeBSD") != 0
Also, I'm personally in contact with Kyle Evans and am familiar with the general interest in making bsdgrep grep. But I also know that it hasn't happened yet.