Use QApplication::desktop for screen size on Qt5

5.15 has QWidget::screen, but older versions don't.

win/Qt/qt_bind.cpp

@@ -95,8 +95,13 @@ NetHackQtBind::NetHackQtBind(int& argc, char** argv) :
 	    lsplash->setFixedSize(pm.size());
 	    lsplash->setMask(QBitmap(pm));
 	}
-	splash->move((splash->screen()->size().width()-pm.width())/2,
+#if QT_VERSION < 0x060000
-		      (splash->screen()->size().height()-pm.height())/2);
+	QSize screensize = QApplication::desktop()->size();
+#else
+	QSize screensize = splash->screen()->size();
+#endif
+	splash->move((screensize.width()-pm.width())/2,
+		      (screensize.height()-pm.height())/2);
 	//splash->setGeometry(0,0,100,100);
 	if ( qt_compact_mode ) {
 	    splash->showMaximized();

win/Qt/qt_main.cpp

@@ -861,9 +861,14 @@ NetHackQtMainWindow::NetHackQtMainWindow(NetHackQtKeyBuffer& ks) :
     setMenu (menubar);
 #endif
 
+#if QT_VERSION < 0x060000
+    QSize screensize = QApplication::desktop()->size();
+#else
+    QSize screensize = screen()->size();
+#endif
     int x=0,y=0;
-    int w=screen()->size().width()-10; // XXX arbitrary extra space for frame
+    int w=screensize.width()-10; // XXX arbitrary extra space for frame
-    int h=screen()->size().height()-50;
+    int h=screensize.height()-50;
 
     int maxwn;
     int maxhn;

win/Qt/qt_menu.cpp

@@ -1133,7 +1133,12 @@ void NetHackQtTextWindow::Display(bool block UNUSED)
 	search.show();
 	rip.hide();
     }
-    int mh = screen()->size().height()*3/5;
+#if QT_VERSION < 0x060000
+    QSize screensize = QApplication::desktop()->size();
+#else
+    QSize screensize = screen()->size();
+#endif
+    int mh = screensize.height()*3/5;
     if ( (qt_compact_mode && lines->TotalHeight() > mh) || use_rip ) {
 	// big, so make it fill
 	showMaximized();