* Add etc/xdg/lubuntu/lightdm/lightdm-gtk-greeter.conf * debian/{postinst,prerm}: install/remove alternatives to use our config as /etc/lightdm/lightdm-gtk-greeter.conf. * debian/control: - add depends on lightdm-gtk-greeter >= 1.0.0-0ubuntu2. - provides lightdm-gtk-greeter-config.