Add Qt libs and headers

paho-mqtt3as-proxy/Qt/include/QtCore/qfactoryinterface.h

@@ -0,0 +1,24 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QFACTORYINTERFACE_H
+#define QFACTORYINTERFACE_H
+
+#include <QtCore/qobject.h>
+#include <QtCore/qstringlist.h>
+
+QT_BEGIN_NAMESPACE
+
+struct Q_CORE_EXPORT QFactoryInterface
+{
+    virtual ~QFactoryInterface();
+    virtual QStringList keys() const = 0;
+};
+
+#ifndef Q_QDOC
+Q_DECLARE_INTERFACE(QFactoryInterface, "org.qt-project.Qt.QFactoryInterface")
+#endif
+
+QT_END_NAMESPACE
+
+#endif // QFACTORYINTERFACE_H