wmaker: Marked args as unused for compiler in menu callback code

When an entry of a menu is selected, the appropriate action is triggered
using a callback, which means having a fixed argument list for that
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/switchmenu.c

@@ -65,6 +65,9 @@ static void focusWindow(WMenu * menu, WMenuEntry * entry)
 	WScreen *scr;
 	int x, y, move = 0;
 
+	/* Parameter not used, but tell the compiler that it is ok */
+	(void) menu;
+
 	wwin = (WWindow *) entry->clientdata;
 	scr = wwin->screen_ptr;