If it is added, it should be appended to the end of the record since it
is an existing record format, then in the case of res=1, errno= should
still be present (not swing in and out) and just contain zero. (Or
another value if there is a non-fatal warning?)
This is not a searchable field, so it can go anywhere. If it is searchable,
ausearch expects ordering of other searchable fields.