PS:
I recall 2-3 notes to users about the evolution of C
post 'vanilla' V6
...
One of the notes is fairly common, but another I have only in hardcopy
(although I scanned it at one point).
More here:
http://minnie.tuhs.org/pipermail/tuhs/2014-October/005218.html
If anyone knows of any other documentation of C evolution, I'd be interested
in hearing about it for the Computer History wiki page.
Noel