Re: jit lock sit-for provokes redisplay provokes imenu

[Richard Stallman]

    Another possibility would be to check the sign of their difference
    instead of comparing them directly.

    Then wraparound is not a problem, instead one of them has to have
    moved more than half the total range away from the other before things
    get ugly.

It might happen less often, but if people really edit a buffer enough
to make the count wrap around, they could do so without saving it,
and this change wouldn't help in such a case.