EXPERIMENTAL: tevent_kqueue support

[Jeremy Allison]

On Tue, Feb 26, 2013 at 01:35:58PM -0800, Jeremy Allison wrote:
> 
> That code was already written carefully to do exactly what
> it does :-).
> 
> Without using threads it's really easy to get yourself
> blocked on a pipe. I'll have to do more testing to see
> if it's true that writable is cleared when a pipe is
> full.

Yep. Just confirmed with junk code. poll returns
writable on a pipe fd even if writing to such a
pipe would block.

That means that for this test we can't always
prioritize writes over reads, as we just end
up blocked in the callback. That's why the
callback code is written as it is, I'm
assuming a pipe can hold 256 btyes without
blocking.

Jeremy.