gtk4x: Avoid deprecated gtk_widget_get_style_context()
Reply To cazfi
at least in gtk4x/gtk5 -client.
I have an almost finished patch that does not use any functions that would require higher than gtk-4.0, and it improves gtk4-client appearance -> likely going to retarget this to 3.1.0-beta4 and gtk4-client.
gtk-4.10 deprecates gtk_widget_get_style_context(). Such calls need to be replaced, at least in gtk4x/gtk5 -client.