Compute Shader & GLSL 4.30 Support For R600 Gallium3D

After recently getting some older Radeon GPUs to OpenGL 4.2 with new R600g patches and making other improvements to R600g, David Airlie has now sent out a set of patches for getting compute shaders and GLSL 4.30 working for some older pre-GCN GPUs with the R600 Gallium3D driver...