环境: Qt5.3.1, mac os x 10.10.1
setWindowFlags(Qt::Window | Qt::WindowTitleHint | Qt::CustomizeWindowHint | Qt::WindowCloseButtonHint);
Qt窗口-仅显示关闭按钮
原文：http://www.cnblogs.com/bugchecker/p/qt_window_only_show_closebtn.html
