Originally Posted by R. Belmont
The sdlmame.lngn.net build actually doesn't allow Metal - it always picks OpenGL for BGFX. I just tried it, you can run with -bgfx_debug to show on-screen what backend it's really using plus some performance data.


Aha! That would explain it then. Good to know it's not some hard-to-find difference in compilers. Sorry for throwing up a red herring...