bug#17647: 24.4.50; accept-process-output with process nil can miss output

[Glenn Morris]

Glenn Morris wrote:

> It returns far too quickly, as if it did not sleep at all.
> I found that (sleep-for 1.0) did nothing, but 
> (sleep-for 0.5) (sleep-for 0.5) worked.

This is http://debbugs.gnu.org/15990, so probably unrelated to recent changes.

> Frankly I have no idea what is going on,

I felt like repeating that...