FIXIDS ( part, nfault, entys, oldids, newids, ifail )
=====================================================

  Fix identifiers in part.

Receives:
  KI_tag_part              *part           --- part in which to fix identifiers

Returns:
 <KI_int_nitems>           *nfault         --- number of entries in lists
 <KI_tag_list_entity>      *entys          --- entities with new identifiers
 <KI_tag_list_int>         *oldids         --- previous identifiers
 <KI_tag_list_int>         *newids         --- new identifiers
  KI_cod_error             *ifail          --- error code


Description:
  FIXIDS searches 'part' for entities with invalid or duplicate identifiers, and
  assigns new unique identifiers to all such entities it finds.

  If there are no faults found, 'nfault' is zero, and no other information is
  returned; otherwise the lists 'entys', 'oldids' and 'newids' are each of
  length 'nfault'.

  'entys' contains the tags of entities to which new identifiers have been
  assigned; the old and new identifiers are returned in corresponding entries in
  'oldids' and 'newids' respectively.

  See IDENID and OUIDEN for further explanation about identifiers.