CAS is broken

[dormando]

Dustin Sallings wrote:
> 
> On Nov 11, 2007, at 14:48, Chris Goffinet wrote:
> 
>> Looks good Dustin, just validated using the latest test from Tomash.
>> Also we need to wrap this in pthread mutex's so its compatible with
>> thread version.
> 
> 
>     Yeah, I almost had a comment out there, but I left it out.  I'm not
> sure whether or not the item allocation is already within a mutex.
> 
>     My goal was to provide a sketch of what I was talking about for
> conceptual review.
> 

For posterity, fix is in r635 from chris (not christ!) and dustin.
I read it, played with it a bit, ran tests, ran it, looked okay.
Runs entirely inside a lock, logic appears sane.

Adds 8 bytes to the item struct.

In it goes.

-Dormando