bug#23632: 25.1.50; Gratuitous undo boundary in latex-insert-block

[Stefan Monnier]

> 1) undo-auto--undoably-changed-buffers becomes an alist

>  ((0 . (buffers*))
>   (1 . (buffers*))
>   (2 . (buffers*)))

> where the key is the return of (recursion-depth)

> 2) undo-auto--boundaries operates only on buffers at the
> current-recursion-depth. Or, probably, at the current of greater
> recursion depth, to ensure that undo-buffers happens when a recursive
> edit exits.

Hmm... sounds pretty good, and I think you can do it more simply:
just let-bind undo-auto--undoably-changed-buffers to nil when entering
a recursive edit.


        Stefan