[Toybox] Does anybody have the diff pdf?

[Rob Landley]

Instead of linking to posix, the diff.c in toybox pending links to
http://cm.bell-labs.com/cm/cs/cstr/41.pdf at the top, but Lucent-alcatel
apparently took that server down in 2015 and it had a robots.txt that prevented
archive.org from preserving its contents. (There's an incomplete mirror of the
"who" directory, but not the "cstr" directory, at
http://cm-bell-labs.github.io/who/ .)

It looks like posix has a reasonable diff description including unified format,
but I'd like to read the old thing to see why the linked to that instead, if
anybody has a copy. (Really that whole directory seems like it had a bunch of
cool computer history stuff in it...)

Rob