Support GTK 4

[Arfrever]

Support for GTK 4 should be added.

GTK 4.0 was released on 2020-12-16:

What’s old

GTK 4 is now stable, and we consider it ready for consumption. That does not mean GTK 3 is dead – we will continue to support and update it for the foreseeable future (the latest release, 3.24.24, quietly went out a few days ago). It does mean, however, that GTK 2 has reached the end of its life. We will do one final 2.x release in the coming days, and we encourage everybody to port their GTK 2 applications to GTK 3 or 4.

(That library can be called GTK+ for versions 1.*, 2.* and 3.*, but it was renamed to GTK (without +) for versions 4.*.)

[dvzrv]

Hi! I maintain hexter for Arch Linux. As gtk2 is now EOL it would be really great if the plugin could be ported to another UI framework (I am aware that it is a major undertaking).

Other popular choices, especially in the plugin context are pugl, JUCE and DPF.

GTK and also Qt are known to crash host software and some host software do not load plugins based on these UI framworks anymore.