The GTK embedding is using a GObject-based interface, rather than the simple-C-plus-C++-wrapper approach of the GLFW (and current Windows) embedding. That means that we will likely need to re-implement the plugin registrar, message channel, method channel, etc. using GObject rather than C++ for the new Linux embedding in order to have a coherent API.

We can wait until the GTK embedding is a bit further along to decide, but I expect that's what we'll end up wanting to do.