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/
For example
```
OIIOOutputDriver::~OIIOOutputDriver()
{
}
```
becomes
```
OIIOOutputDriver::~OIIOOutputDriver() {}
```
Saves quite some vertical space, which is especially handy for
constructors.
Pull Request: https://projects.blender.org/blender/blender/pulls/105594
Even though the `no_unique_address` attribute has only been standardized
in C++20, compilers seem to support it with C++17 already. This attribute
allows reducing the memory footprint of structs which have empty types as
data members (usually that is an allocator or inline buffer in Blender).
Previously, one had to use the empty base optimization to achieve the same
effect, which requires a lot of boilerplate code.
The types that benefit from this the most are `Vector` and `Array`, which
usually become 8 bytes smaller. All types which use these core data structures
get smaller as well of course.
Differential Revision: https://developer.blender.org/D14993
