[PATCH][V3][xserver] configure.ac: add option for xshmfence

[Matt Turner]

On Fri, Aug 15, 2014 at 8:16 AM, Keith Packard <keithp at keithp.com> wrote:
> Ross Burton <ross.burton at intel.com> writes:
>
>> xshmfence is usable outside of DRI3, and is currently autodetected which isn't
>> good for distributions where deterministic builds are desired.
>>
>> Signed-off-by: Ross Burton <ross.burton at intel.com>
>
> Seems like this should work;
>
> Reviewed-by: Keith Packard <keithp at keithp.com>

You already pulled in a newer version of this patch (commit 4afedf545b67).