Rewrite the configure GTK and WebKitGTK test section. The old code was way too confusing and complicated with nested ifs. Simplify the code with a primary and alternate webkit package. Display the selected GTK version and WebKit package during configure. This change removed a "WebKitGtk" package, which I am not sure what it was from... but if it causes problems revisit later. --with-gtk4 will override --with-gtk2 now and will always default to GTK3. If --with-gtk2 is used with no GTK2 installed or --with-gtk4 is used with no GTK4 installed use GTK3. Then in a second pass we check the package we have selected and add any necessary defines so the correct code paths are followed during compile.