The dip code for S/Key has always been broken on Linux/x86.
(Someone used "dos" as a proxy for "x86", which is wrong.)
The code is still self-consistent, but will not work with a
big-endian server such as a Sparc. The (recent?) definition
of LITTLE_ENDIAN in /usr/include/endian.h means that the
Sparc code will now probably mis-compile as well.
I will post a fix when I get a bug number.
Fixed in dip-3.3.7o-15. Thanks for the patch.