egl/glx: Remove egl_glx driver

Mesa now has a real, feature-rich EGL implementation on X11 via xcb.
Therefore I believe there is no longer a practical need for the egl_glx
driver.

Furthermore, egl_glx appears to be unmaintained.  The most recent
nontrivial commit to egl_glx was 6baa5f1 on 2011-11-25.

Tested by running weston-smoke in windowed Weston on X with i965.

Signed-off-by: Chad Versace <chad.versace@linux.intel.com>
Acked-by: Kenneth Graunke <kenneth@whitecape.org>
Acked-by: Kristian Høgsberg <krh@bitplanet.net>

docs/egl.html

@@ -232,16 +232,6 @@ The supported platforms are X11, DRM, FBDEV, and GDI.</p>
 
 </dd>
 
-<dt><code>egl_glx</code></dt>
-<dd>
-
-<p>This driver provides a wrapper to GLX.  It uses exclusively GLX to implement
-the EGL API.  It supports both direct and indirect rendering when the GLX does.
-It is accelerated when the GLX is.  As such, it cannot provide functions that
-is not available in GLX or GLX extensions.</p>
-</dd>
-</dl>
-
 <h2>Packaging</h2>
 
 <p>The ABI between the main library and its drivers are not stable.  Nor is
@@ -262,10 +252,6 @@ is disabled by default.</p>
 <code>src/egl/</code>.  The sources of the <code>egl</code> state tracker can
 be found at <code>src/gallium/state_trackers/egl/</code>.</p>
 
-<p>The suggested way to learn to write a EGL driver is to see how other drivers
-are written.  <code>egl_glx</code> should be a good reference.  It works in any
-environment that has GLX support, and it is simpler than most drivers.</p>
-
 <h3>Lifetime of Display Resources</h3>
 
 <p>Contexts and surfaces are examples of display resources.  They might live