/*
 * call-seq:
 *      attach_to( widget )
 *
 * widget = The widget (or a Gtk::StatusIcon, when compiled against GTK+ >= 2.9.2 and libnotify >= 0.4.1) to attach to
 *
 * Attaches the notification to a widget/Gtk::StatusIcon
 */
static VALUE
notification_attach( VALUE self, VALUE widget ) {