LU-2743 introduced a regression into lustre_idl.h. One reason that it no longer compiles in installed user space because of this addition:

#include <lustre/lustre_errno.h>

But lustre_errno. is not packaged.

There are two questions that need answering:

• Should lustre_idl.h really include lustre_errno.h?
• Should lustre_errno.h really be a new interface exposed to user space?

If the answers to both are "yes", we can consider packaging lustre_errno.h.

Of course, we also need to decide if we will continue packaging luste_idl.h (see parent issue LU-1606). If we stop packaging it, then this ticket is moot.