func (v *SList) Foreach(fn func(ptr unsafe.Pointer)) {
	for l := v; l != nil; l = l.Next() {
		fn(unsafe.Pointer(l.native().data))
	}
}
func (v *SList) Foreach(fn func(ptr unsafe.Pointer)) {
	for l := v; l != nil; l = l.Next() {
		fn(unsafe.Pointer(l.native().data))
	}
}
// Foreach acts the same as g_slist_foreach().
// No user_data argument is implemented because of Go clojure capabilities.