Simple garbage collector

I wonder if it would be possible to add a second option for GC, like a simple mark and sweep (of course, what’s simple these days?) but anyway it might be nice to have an alternative GC in case the built-in one is hard to…grok ex: https://github.com/crystal-lang/crystal/issues/3997

Just thinking out loud, I guess there aren’t too many complaints about it…

Or maybe even some other non boehm GC’s could be alternatives (not sure what exists out there, here’s a couple: https://stackoverflow.com/a/26619508/32453) FWIW :)