I hadn’t gotten around to updating my Mac to Yosemite yet, so I hadn’t updated the homebrew formula for bsdgames-osx yet. Happily, though, some enterprising person went and did so. There’s now an updated homebrew bsdgames-osx formula for Yosemite. BINOWN and friends need to be set for bsdmake to work right now, which is why the old formula wasn’t working anymore.