Copyright for des_crypt.3:

@(#)des_crypt.3	2.1 88/08/11 4.0 RPCSRC; from 1.16 88/03/02 SMI;

Taken from libc4 sources, which say:
Copyright (C) 1993 Eric Young - can be distributed under GPL.

However, the above header line suggests that this file in fact is
Copyright Sun Microsystems, Inc (and is provided for unrestricted use,
see other Sun RPC sources).

License for des_crypt.3:

can be distributed under GPL.