[PATCH] XFS: Fix gcc 4.6 set but not read and unused statement warnings v2

[Andi Kleen]

> really?
>
> $ make SUBDIRS=fs/xfs
>    CC [M]  fs/xfs/linux-2.6/xfs_super.o
> fs/xfs/linux-2.6/xfs_super.c:73:2: error: #error DEBUG
> make[1]: *** [fs/xfs/linux-2.6/xfs_super.o] Error 1
>
> $ grep -A3 XFS_DEBUG fs/xfs/linux-2.6/xfs_super.c
> #ifdef CONFIG_XFS_DEBUG
> #error DEBUG
> #endif
>
> (above just for testing)
>
> Offtopic I guess, but it sure seems to set it for me.

You did a full build with XFS_DEBUG before without SUBDIRS, right?

Kbuild puts the options into special .cmd files and I think
those only get rebuild on a full build, not on a SUBDIRS
build. So it never picked up the changed option for me.

Anyways that's the current theory, haven't retested that.

-Andi