These files come from the 2.11BSD sources as posted by the
The Unix Heritage Society, TUHS (http://www.tuhs.org). They are
close derivatives of the same files in the Unix V7 sources as
posted by the same organization. The copyright status of these files
is complex:

- Some would argue that these files did not carry a (c) claim,
and that prior to the USA ratifying the Berne convention this implied
that they became the public domain in the 1970's.

- The SCO Group, which owned the copyrights (if any) in the 1990's
granted a license for non-commerical research use.

- In 2002, Caldera (which purported to own the copyrights at that
point in time) released the files under a 4-clause BSD-style license.
In 2007 the courts ruled that not Caldera but Novell owned the
copyrights (if any). However, Caldera was entitled to give out
licenses. Novell has since acted as if it endorsed the Caldera
license and made public pledges not to sue.

- In summary, the files are either public domain or BSD-licensed
with Novell (now part of Attachmate) being the licensor.

- These files were updated to work with modern C and modern
compilers by the BKUNIX project (Serge Vakulenko, vak@cronyx.ru).
The updates are of a mechanical nature, see:
http://sourceforge.net/p/bkunix/code/40/
It is debatable whether such updates are coprightable, but to
the extent they are, Serge later re-licensed his modifications under
the GPL license.

- In summary, if you want to redistribute these files you must either:
  (i) obey by the rules of the GPL
  (ii) recreate the mechanical updates independently

In any case, private use of these files is permited by all parties
and licenses. Considering we are talking about 40 year old software
for obsolete systems, private hobby projects are probaly the only actual
use these files have.
