Intel Mesa Driver Code Working To Split Off Old Broadwell "Gen8" Graphics Code

Intel's Iris Gallium3D driver for modern OpenGL support works on hardware going back to old Broadwell processors with "Gen8" integrated graphics as does the HasVK Vulkan driver for Haswell/Broadwell. But in allowing to focus on the common Skylake "Gen9" graphics and newer/future Intel graphics architectures, pending Mesa code is working to split-off that old Broadwell/Gen8 code. The Gen8 support will continue to be in-tree but separated from the rest of the compiler code so that the code can continue to be improved for newer Intel hardware without risking regressions/breaking those still on Broadwell era processors...