contrib: add a script to build all of the wheels on macOS This is mostly a translation of `contrib/packaging/build-windows-wheels.bat`, except the default pythons to build can be inferred from `setup.py` and/or `pyproject.toml`, and all use the same configuration. All we need to do is force the building of translation files, tell it to skip pypy wheels, and tell it to build universal2 wheels instead of for the current architecture.

rhg-status: rename a variable to be more explicit Possibly we would have caught the looming bug earlier if this had been named closer to what it actual is used for.

rhg-status: use `Filelog` default options when opening filelogs This is not currently a problem since the options are the same, but would have become one at some point in the future.