gtkQuitAdd this function adds the possibility to
pass a marshaller and a function to be called when the quit handler is freed.gtkQuitAddFull(main.level, fun, data = NULL)main.leveldatafunction.gtkQuitRemove)
or 0 if you passed a NULL pointer in function.data (while
you can do this in function as well)... So this function will mostly be
used by GTK+ wrappers for languages other than C.