Make winbind use epoll where available

[Jeremy Allison]

On Thu, Jan 17, 2013 at 04:57:26PM +0100, Volker Lendecke wrote:
> Hi!
> 
> Attached find a patchset to make winbind use the standard
> tevent_context_init function which uses epoll where
> available. Before this winbind would always do poll. Ran a
> successful private autobuild.
> 
> One customer test brought winbind from 100% CPU over minutes
> down to barely being seen in "top" for obvious reasons.
> 
> Comments?

Looks (and tests) good to me. Pushed to autobuild.

FYI. I'm also working on a change to fix tevent_standard
to fallback to poll rather than select.

It removes a *lot* of duplicate code from tevent_standard.c
(in fact all of it - it no longer contains a duplicate of
the epoll code :-).

I'll propose to the list for your and metze review once it passes
testing :-).

Jeremy.