Build fails on Linux in CTF

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

Building amd64 on a linux host.  Build fails in tools/libctf with

tools/libctf/../../external/cddl/osnet/sys/sys/uio.h:77:15: error: field 'uio_segflg' has incomplete type
  enum uio_seg uio_segflg;
               ^
tools/libctf/../../external/cddl/osnet/sys/sys/uio.h:78:14: error: field 'uio_rw' has incomplete type
  enum uio_rw uio_rw;
              ^

etc...

-uwe