This topic adds support for building a wheel (`.whl`) for VTK. This is done by generating a `setup.py` file in VTK's build tree during its configuration step which then can be used to complete the build and make a wheel. It does not support making a valid `sdist` file because the `setup.py` is not the entry point to this build. The reason that things are done this way is because VTK's configuration logic is complicated and reimplementing it in `setup.py` is not maintainable. Instead, it takes whatever VTK is built and packages it up. When this mode is used, the sole purpose of the build tree is to build a wheel; it is not a general-purpose VTK build tree. This is because the structure expected by the `bdist_wheel` command is accomplished by setting output directories which causes standard things such as `bin` and `lib` to not be included.
This will likely be split into a separate MR (!5544 (merged)) to get the "easy" fixes and such in earlier. than this is likely to land.
support marking the wheel with "feature" flags for what is actually contained in it
documentation for building a wheel
sdistcommand pointing to aforementioned instructions