hlsl_parser: Remove D3D9/GL const defs, register allocations and glsl wrappers rendersystem: RenderContext set their associated thread index from RenderSystem_GetThreadIndex() instead of Plat_GetThreadIndex(), this avoids counting non-rendering threads keeping us well within our MaxDeviceAccessThreads If we didn't find error shader don't bother trying to find a fallback you wouldn't get, just remove the layer, allows us to compile shaders from scratch with everything removed Small HLSL syntax fixes for DXC + Vulkan (FXC is less strict)