bug#15045: Point jumps inappropriately around time of Semantic lexing

[Stefan Monnier]

> If arbitrary timers can execute during the lexer's call to
> accept-process-output or input-pending-p, then doesn't that mean
> jit-lock-deferred-fontify can run too?

Yes.

> If removing timers' sit-for calls is the solution,

It's a workaround.

> then what's to become of jit-lock-deferred-fontify's call to sit-for?
> Doesn't deferred jit locking necessarily have to call redisplay?

Yes, tho I guess if absolutely needed, we could probably arrange for
jit-lock-deferred-fontify not to call sit-for.  I'm not completely sure
how that could work, but it doesn't sound impossible.


        Stefan