minor improve quick demo

Zhao Yuhang

2023-12-18 44fee9aa1e3087635d1394612c6f6ceab44ba7b0

 src/quick/quickwindowagent_p.h

@@ -16,6 +16,10 @@

        // Host
        QQuickWindow *hostWindow{};

#ifdef Q_OS_WINDOWS
        void setupWindows10BorderWorkaround();
#endif
    };

}