flag parameters: check magic constants

This patch adds test that ensure the boundary conditions for the various
constants introduced in the previous patches is met.  No code is generated.

[akpm@linux-foundation.org: fix alpha]
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 3fd4014..2fdad42 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1051,6 +1051,9 @@
 	int error, fd = -1;
 	struct eventpoll *ep;
 
+	/* Check the EPOLL_* constant for consistency.  */
+	BUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC);
+
 	if (flags & ~EPOLL_CLOEXEC)
 		return -EINVAL;