A lot of files were missing copyright field in the header and
the Blender Foundation contributed to them in a sense of bug
fixing and general maintenance.
This change makes it explicit that those files are at least
partially copyrighted by the Blender Foundation.
Note that this does not make it so the Blender Foundation is
the only holder of the copyright in those files, and developers
who do not have a signed contract with the foundation still
hold the copyright as well.
Another aspect of this change is using SPDX format for the
header. We already used it for the license specification,
and now we state it for the copyright as well, following the
FAQ:
https://reuse.software/faq/
The runtime backup/restore logic was slightly wrong: it is possible that
an object requires light linking runtime but does not need light linking
itself. This is typical configuration for the receivers/blockers.
Modified the logic so that the evaluated object light linking is allocated
if there was a runtime field needed.
This required to make it so light linking evaluation takes care of feeing
the light_linking if it is empty. The downside of this approach is a
redundant allocation from the object backup when removing light linking
collection from emitter. But this is not a typical evaluation flow, and
the more typical flows are cheap with this approach.
Pull Request: https://projects.blender.org/blender/blender/pulls/108261
