Fix compiling examples with -no-sm

There is access to session manager functions which are not present when
building with -no-sm.

Change-Id: I1c92b4a70f7adb56816877930fb9f55b04ff8940
Reviewed-by: Andy Shaw <andy.shaw@theqtcompany.com>

examples/widgets/mainwindows/application/mainwindow.cpp

@@ -59,9 +59,11 @@ MainWindow::MainWindow()
     connect(textEdit->document(), &QTextDocument::contentsChanged,
             this, &MainWindow::documentWasModified);
 
+#ifndef QT_NO_SESSIONMANAGER
     QGuiApplication::setFallbackSessionManagementEnabled(false);
     connect(qApp, &QGuiApplication::commitDataRequest,
             this, &MainWindow::commitData);
+#endif
 
     setCurrentFile(QString());
     setUnifiedTitleAndToolBarOnMac(true);
@@ -387,7 +389,7 @@ QString MainWindow::strippedName(const QString &fullFileName)
     return QFileInfo(fullFileName).fileName();
 }
 //! [49]
-
+#ifndef QT_NO_SESSIONMANAGER
 void MainWindow::commitData(QSessionManager &manager)
 {
     if (manager.allowsInteraction()) {
@@ -399,3 +401,4 @@ void MainWindow::commitData(QSessionManager &manager)
             save();
     }
 }
+#endif

examples/widgets/mainwindows/application/mainwindow.h

@@ -70,7 +70,9 @@ private slots:
     bool saveAs();
     void about();
     void documentWasModified();
+#ifndef QT_NO_SESSIONMANAGER
     void commitData(QSessionManager &);
+#endif
 
 private:
     void createActions();