ops.h references NULL, so include stddef.h, so files including ops.h
don't have to.
Signed-off-by: Scott Wood <scottwood@freescale.com> Acked-by: Mark A. Greer <mgreer@mvista.com> Acked-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>