xconfig: Abort close if configuration cannot be saved

Give the user an opportunity to fix the error or save the configuration
under a different path.
Reported-by: Hiromu Yakura <hiromu1996@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/kconfig/qconf.cc

@@ -1478,10 +1478,13 @@ void ConfigMainWindow::loadConfig(void)
 	ConfigView::updateListAll();
 }
 
-void ConfigMainWindow::saveConfig(void)
+bool ConfigMainWindow::saveConfig(void)
 {
-	if (conf_write(NULL))
+	if (conf_write(NULL)) {
 		QMessageBox::information(this, "qconf", _("Unable to save configuration!"));
+		return false;
+	}
+	return true;
 }
 
 void ConfigMainWindow::saveConfigAs(void)
@@ -1642,7 +1645,11 @@ void ConfigMainWindow::closeEvent(QCloseEvent* e)
 	mb.setButtonText(QMessageBox::Cancel, _("Cancel Exit"));
 	switch (mb.exec()) {
 	case QMessageBox::Yes:
-		saveConfig();
+		if (saveConfig())
+			e->accept();
+		else
+			e->ignore();
+		break;
 	case QMessageBox::No:
 		e->accept();
 		break;

scripts/kconfig/qconf.h

@@ -311,7 +311,7 @@ public slots:
 	void listFocusChanged(void);
 	void goBack(void);
 	void loadConfig(void);
-	void saveConfig(void);
+	bool saveConfig(void);
 	void saveConfigAs(void);
 	void searchConfig(void);
 	void showSingleView(void);