I whacked this around some more, added basic docs, and committed it.
Thanks!
> Unfortunately rl_clear_screen() is not included at all in libedit, causing > compilation to fail, and I was completely unable to find a way to > distinguish libedit from readline on OS X. It tries extraordinarily hard to > pretend that it's readline. Instead falling back to simple control > characters to clear the screen worked very well on both linux and OS X.
I took that out; "works on the two cases I tried" does not mean "portable".
Completely understandable.
I'm very excited to have helped contribute something, however small this was, to the project.