Add wayland 1.0.2.
Add mesa 9.0.x and corresponding libdrm.

I took most of the changes from falsifian's repo, but I want to keep mesa 9.0
as a separate expression. For now I added wayland as a mandatory dependency,
will have to fix that.
Add libxkbcommon 0.2.0.

This is needed as a dependency for the Weston compositor.
Add support for gl backend to cairo.

This is also needed for the Weston compositor.
Add Weston 1.0.2.

Currently doesn't build. I have to further investigate but there seems to be a
missing file from the tarball.
Weston: add patches to fix the build.

The patches fix two issues:
 - screenshooter-client-protocol.h missing from tarball
 - missing flags for include paths and definitions
I had to add auto* as inputs to be able to call autoreconf, as one patch
modifies a Makefile.am. Both issues are already reported upstream.
Weston: prevent install to chown root weston-launch.

This operation fails with permission denied, and since this launcher is only
needed when not running under X, I leave it disabled for the moment.
Merge branch 'wayland' of https://github.com/cpages/nixpkgs into wayland