http://www.6809.org.uk/xroar/
Something that might be interesting is that joysticks should now be hotplug (so long as you build with libevdev around under Linux, or use SDL) - new controllers should appear in the menu when you plug them in.
Now my tests under Windows imply this isn't super reliable there - in particular subsequent replugs seem to see my bog standard Logitech F310 differently than when XRoar first starts - but worst case is it's a little better than before.
And...
It'll try and do intelligent things with game controllers - if you have left and right sticks on just the one device, by default you'll find the sticks mapped to the right/left ports. Useful for Robotack? And possibly little else
But because no two controllers are the same, you can specify an SDL mapping file (even if you're not using SDL) - check out https://github.com/mdqinc/SDL_GameControllerDB for a good example.
And...
For those that were used to building against GTK+ 2, I backported all the changed stuff to that so your experience should be just as good as the newer GTK+ 3 UI. I'm calling GTK+ 2 support deprecated, but I'll probably keep it going for as long as it's part of Debian.