Solve the problem of undefined reference to `vtable for MiniStackPrivateT'

MiniStack.cpp is a custom control program. The defined MiniStackPrivateT QObject object class reports an error.

报错1：
undefined reference to `vtable for MiniStackPrivateT’

Error 2:
undefined reference to `MiniStackPrivateT::staticMetaObject'

Solution:
Comment out Q_OBJECT