Enable gtk4-client by --enable-client=all
--enable-client=all should build also gtk4-client when possible. That was disabled earlier when gui-gtk-4.0 did not build against stable gtk4 library but earlier development snapshots only. That's no longer the case.
--enable-client=all should build also gtk4-client when possible. That was disabled earlier when gui-gtk-4.0 did not build against stable gtk4 library but earlier development snapshots only. That's no longer the case.