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>
diff --git a/scripts/kconfig/qconf.h b/scripts/kconfig/qconf.h
index 91677d9..3715b3e 100644
--- a/scripts/kconfig/qconf.h
+++ b/scripts/kconfig/qconf.h
@@ -311,7 +311,7 @@
 	void listFocusChanged(void);
 	void goBack(void);
 	void loadConfig(void);
-	void saveConfig(void);
+	bool saveConfig(void);
 	void saveConfigAs(void);
 	void searchConfig(void);
 	void showSingleView(void);