[purego] PoC for FreeBSD and Linux

[JupiterRider]

(Don't merge, this is just a proof of concept for discussion.)

purego supports FreeBSD and Linux, but it doesn't support passing or returning structs on these platforms, so I created a libffi binding as workaround.

I implemented some raylib functions in this pull, to show how the code could look like.

@gen2brain What do you think?

[gen2brain]

Very nice that it works, and libffi should be everywhere by default, but the first thing I thought was that it would be yet another binding that needs to be maintained, a third one. What about purego, is there a chance passing structs would be implemented for Linux? I think I saw some work done on this subject but for macOS.

[JupiterRider]

What about purego, is there a chance passing structs would be implemented for Linux? I think I saw some work done on this subject but for macOS.

Yes, there is a chance, but I don't know when it will come: ebitengine/purego#236

Very nice that it works, and libffi should be everywhere by default, but the first thing I thought was that it would be yet another binding that needs to be maintained, a third one.

I agree! We don't even have a solution jet to compare the API (cgo <-> !cgo).