Re: Undo discard prompt (was: [T. V. Raman] read-only modes should be using buffer-disable-undo?)

[Richard Stallman]

    If the large undo entry is accumulated by a timer or asynchronous
    process, the user may not even be at his monitor when the question is
    asked.

In most cases, subprocess output should combine into a single
insertion undo entry, which is just one cons cell.  So it will never
trigger this question.

There are reports that this combining isn't working in some cases.
Let's debug them and fix them to do this right, not compensate for
their failure to do so.

As for timers, they should be written so as to not accumulate undo
data into a single entry.  We already determined that.