@jk Thank you, i am on 10.9.5, x11 is present (seems avail. all the way down to 10.6.8 at least).
However, I'd have to do this without brew...
@jayrope When to comes to X11, that shouldn't be needed AFAIK. SDL uses the native Mac graphics and/or OpenGL.
Checking out MacPorts, they might have everything you need, though: https://ports.macports.org/port/libsdl2/details/
@jayrope No such plans at the moment. SDL2 seems to be able to target down to 10.6, but all the other dependencies would have to be rebuilt as well. It is probably doable, but even if I had the time I wouldn't be able to verify if the result actually works on anything older than 10.13.
I can provide guidance if you want to try compiling everything yourself, though.
Availability of a C11 compiler might be a problem on very old OS X versions.