R600 Gallium3D Driver For Old Radeon GPUs To See Rewritten NIR Backend

While AMD's official graphics driver on Windows has effectively moved to legacy pre-Polaris graphics card support, in the open-source world on Linux even the old "R600" Gallium3D driver for Radeon HD 2000 through HD 6000 series graphics cards sees the occasional new feature work by the community. The latest is a new NIR back-end being rewritten for this R600g driver and should debut soon...