https://wiki.blender.org/wiki/Building_Blender/CUDA
Wiki says to edit cmake config, add path to optix sdk like this:
WITH_CYCLES_DEVICE_OPTIX=ON
OPTIX_ROOT_DIR=/path/to/NVIDIA-OptiX-SDK-7.x.x-xxx
Wondering if this is still necessary because it already has this:
OPTIX_INCLUDE_DIR:PATH=C:/ProgramData/NVIDIA Corporation/OptiX SDK 7.0.0/include