[PATCH] Link error when futexes are disabled on 64bit architectures

If futexes are disabled we fail to link on ppc64.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

kernel/exit.c

@@ -898,7 +898,7 @@ fastcall NORET_TYPE void do_exit(long code)
 	}
 	if (unlikely(tsk->robust_list))
 		exit_robust_list(tsk);
-#ifdef CONFIG_COMPAT
+#if defined(CONFIG_FUTEX) && defined(CONFIG_COMPAT)
 	if (unlikely(tsk->compat_robust_list))
 		compat_exit_robust_list(tsk);
 #endif