Specify Q_DISABLE_COPY where appropiate

src/mqtt/qmqttclient.h

@@ -117,6 +117,7 @@ public slots:
     void setPassword(QString password);
 
 private:
+    Q_DISABLE_COPY(QMqttClient)
     Q_DECLARE_PRIVATE(QMqttClient)
 };
 

src/mqtt/qmqttconnection_p.h

@@ -105,6 +105,7 @@ public:
     bool m_ownTransport{false};
     QMqttClient *m_client{nullptr};
 private:
+    Q_DISABLE_COPY(QMqttConnection)
     bool writePacketToTransport(const QMqttControlPacket &p);
     QMap<quint16, QSharedPointer<QMqttSubscription>> m_pendingSubscriptionAck;
     QMap<quint16, QSharedPointer<QMqttSubscription>> m_pendingUnsubscriptions;

src/mqtt/qmqttsubscription.h

@@ -65,6 +65,7 @@ public slots:
     void unsubscribe();
 
 private:
+    Q_DISABLE_COPY(QMqttSubscription)
     friend class QMqttConnection;
     friend class QMqttClient;
     explicit QMqttSubscription(QObject *parent = nullptr);