gtk/window.go
func (v *Window) SetIconFromFile(file string) error {
	cstr := C.CString(file)
	defer C.free(unsafe.Pointer(cstr))
	var err *C.GError = nil
	res := C.gtk_window_set_icon_from_file(v.native(), (*C.gchar)(cstr), &err)
	if res == 0 {
		defer C.g_error_free(err)
		return errors.New(C.GoString((*C.char)(err.message)))
	}
	return nil
}
func (v *Window) SetIconFromFile(file string) error {
	cstr := C.CString(file)
	defer C.free(unsafe.Pointer(cstr))
	var err *C.GError = nil
	res := C.gtk_window_set_icon_from_file(v.native(), (*C.gchar)(cstr), &err)
	if res == 0 {
		defer C.g_error_free(err)
		return errors.New(C.GoString((*C.char)(err.message)))
	}
	return nil
}
// SetIconFromFile is a wrapper around gtk_window_set_icon_from_file().