libthreads provenance

Uncle Thomas, can you tell us a story?  I want to hear the one about where
the cthreads code came from and what its name and personal identification
number were in its native land of CMU.  

I've been looking at MK83a (old dist still at
ftp://ftp.cs.cmu.edu/afs/cs/project/mach/public/src/mkernel), which is the
place I've located the original alpha code.  The libthreads in there is
marginally different from MK83 aside from having the alpha port.  The UK22
version (and Utah's internal mach4 repository to this day) matches MK83.  

It sure looks like hurd/libthreads started with a CMU version older than
MK83.  I would ideally like to merge it all together by applying the GNU
changes to the MK83 or MK83a code.  But for that I need to find the
pristine CMU version that the hurd version forked from.  Otherwise it will
just be purely by hand and that will make me more grumpy.