wmaker: Marked args as unused for compiler in WINGs Notif callback code

The mechanism of Notifications in the WINGs toolkit is relying on
callbacks to dispatch notifications, which means having a fixed argument
list for the handling function.

It is then correct to not use all the arguments, so this patch adds the
appropriate stuff to avoid a false report from compiler.

Signed-off-by: Christophe CURIS <christophe.curis@free.fr>

src/icon.c

@@ -93,6 +93,9 @@ static void tileObserver(void *self, WMNotification *notif)
 {
 	WIcon *icon = (WIcon *) self;
 
+	/* Parameter not used, but tell the compiler that it is ok */
+	(void) notif;
+
 	update_icon_pixmap(icon);
 
 	XClearArea(dpy, icon->core->window, 0, 0, 1, 1, True);