Сделать ctor (s) приватными.
class not_derivable { private: not_derivable(){} };
class derived : public not_derivable {};
int main() { derived d; // diagnostic }
или дтор:
class not_derivable { private: ~not_derivable(){} };
class derived : public not_derivable {};
int main() { not_derivable *nd = new not_derivable; derived d; //diagnostic }