All linux CI machines have gtk3 installed. And Python GTK things are too complicate to setup. Pick-to: 6.4 6.3 6.2 5.15 Change-Id: I3c0d967f61aebea508784df79569b9d0064f66e2 Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>