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.