[Pixman] add enable-cache-prefetch option

[Soeren Sandmann]

Liu Xinyun <xinyun.liu at intel.com> writes:

>    This patch is to add a new configuration option: enable-cache-prefetch,
> which is default yes.
> 
>    Here is a link which talks on cache issue.
>    http://lists.freedesktop.org/archives/pixman/2010-June/000218.html
> 
>    When disable it on Atom CPU(configured with --enable-cache-prefetch=no),
> it will have a little performance gain. Here is the patch.

I think the cache prefetch code should just be deleted outright. No
benchmarks that I'm aware of show it to be an improvement.


Thanks,
Soren