code: func ToolButtonNew(iconWidget IWidget, label string) (*ToolButton, error) {
  	cstr := C.CString(label)
  	defer C.free(unsafe.Pointer(cstr))
  	w := nullableWidget(iconWidget)
  	c := C.gtk_tool_button_new(w, (*C.gchar)(cstr))
  	if c == nil {
  		return nil, nilPtrErr
  	}
  	return wrapToolButton(glib.Take(unsafe.Pointer(c))), nil
  }
docs: // ToolButtonNew is a wrapper around gtk_tool_button_new().