My MacOS setup for hacking on CRuby

I recently posted my docker setup for hacking on CRuby , which showed how I test Linux features when working on CRuby. But most of the time, I just build CRuby directly on MacOS. The Building Ruby guide from ruby-lang.org is the most up-to-date guide on doing this, but I like to spell it out exactly in order of how I do it day-to-day. So this is for me more than anything, but you may find it…