[cairo] [PATCH cairo] Drop the experimental skia backend

[Adrian Johnson]

On 22/08/17 07:17, Bryce Harrington wrote:
> As has been stated in the README, skia is not API stable and is not
> available packaged, versioned forms, resulting in it being a continually
> moving target.  So the cairo skia backend has to be updated continually
> as the skia API morphs, which means in practice that Cairo's skia
> backend will always work only with a specific snapshot and lacking a
> high degree of maintenance activity will always be badly out of date.
> The last time the cairo skia backend was updated was in 2014, and had
> not been updated very regularly prior to that.

Could we just comment it out in configure.ac to avoid presenting it as
an option to users?