[arch-general] Mesa 9.1 in testing

New unified Mesa has hit testing. Upgrade path went smooth here. Please test it. Now the main mesa pkg should provide everything required to build and link packages. The mesa-libgl pkg providing libgl should be not be used in the dependency array when linking to libgl.so - please use "libgl" that will allow users to choose also nvidia-utils or catalyst-utils. There are still packages in extra depending on the old libgl package. We will need to fix them before makepkg will properly allow to build only against new mesa. -Andy