Shrink task_struct if CONFIG_FUTEX=n

robust_list, compat_robust_list, pi_state_list, pi_state_cache are
really used if futexes are on.

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/fork.c b/kernel/fork.c
index 8a97e92..3e764f6 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1156,13 +1156,14 @@
 	 * Clear TID on mm_release()?
 	 */
 	p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL;
+#ifdef CONFIG_FUTEX
 	p->robust_list = NULL;
 #ifdef CONFIG_COMPAT
 	p->compat_robust_list = NULL;
 #endif
 	INIT_LIST_HEAD(&p->pi_state_list);
 	p->pi_state_cache = NULL;
-
+#endif
 	/*
 	 * sigaltstack should be cleared when sharing the same VM
 	 */