gtk/print.go
func (ps *PageSetup) SetOrientation(orientation PageOrientation) {
	C.gtk_page_setup_set_orientation(ps.native(), C.GtkPageOrientation(orientation))
}
func (ps *PageSetup) SetOrientation(orientation PageOrientation) {
	C.gtk_page_setup_set_orientation(ps.native(), C.GtkPageOrientation(orientation))
}
// SetOrientation() is a wrapper around gtk_page_setup_set_orientation().