There is no prompt in the engine. You can see the code in the ./cocos/platform/CCCommon.h and associated implementations are in each folder: CCCommon-ios.mm, CCCommon-mac.mm, CCCommon-android.java. Looks like linux is not supported yet. You could probably duplicate it into a prompt (two button) version, except that the callback will be more work and a little tricky. I’ve done this prompt for testing iAP in iOS/Mac/Android, but it’s not in a nice format like plugin-x will hopefully do in the future.
void CC_DLL MessageBox(const char * msg, const char * title);
// usage (it's in global namespace)
MessageBox("Congrats on completing the game!", "Victory");