Add support for MacOS

[arthrp]

Currently MacOS is not supported. Adding support shouldn't be too hard as osx libsdl2 binaries are available. I can look into that if you agree with adding the support.

[nstlaurent]

That is fine but Helion as a whole doesn't support MacOS currently. The first known roadblock is that it uses geometry shaders to render sprites that M1 Macs do not support. I also don't own one to verify anything I do would function.