Sounds like anything built on an Intel Mac will work with the new M1 macs bases on what I've been hearing.

The question is if the reverse is true or not: If I build MAME on an M1 mac and distribute the executable, will it be playable on older macs?

I don't yet own an M1 mac but planning on replacing my Mac Mini with the latest model this spring. I've been building MAME for years and distributing the Windows and Mac 64-bit builds on Usenet newsgroups still and wondering how portable that code is, or if I need to keep building it on my 8-year-old machine that takes over 3 hours to build. smile