[PATCH xserver] configure.ac: bump epoxy requirement to 1.2

[Adam Jackson]

On Tue, 2016-10-25 at 08:50 -0700, Eric Anholt wrote:

> I've said it before a couple of times, but it stands: The next step for
> epoxy is that someone needs to look into YaronCT's fork and decide if we
> should just bless it as the maintained upstream.

Just read through the diff between your branch and Yaron's, it all
looks good to me. Including a epoxy_egl_get_current_gl_context_api fix
that I'd independently written long after the fact.

I'll move my pull requests over.

- ajax