Changing 3D curve properties while viewport rendering was active
resulted in an error, because Cycles would attempt to update the
acceleration structure containing the curves, but that acceleration
structure was built without the
`OPTIX_BUILD_FLAG_ALLOW_UPDATE` flag allowing updates. This
fixes that by adding the flag to all curve build inputs.
Ideally could just use the same flags as for other build inputs and
differentiate between viewport and final rendering (based on
`bvh_type`), but that's not currently an option since the same flags
have to be specified to query the curve intersection module in
`load_kernels()`, where that differentiation is not known. See also
commit 5c6053ccb1.
Pull Request: https://projects.blender.org/blender/blender/pulls/129634
5804a1cc2c