Bugzilla

I seem to have worked around this locally, possibly by installing the `zstd` package in my `.mozbuild/_virtualenvs/mach` directory, though I'm not entirely sure if that's what did it.

I don't know if these steps are advisable, but for the record, the steps that may've worked around this for me were:
```
cd /path/to/.mozbuild/_virtualenvs/mach
source ./bin/activate 
pip install zstd
```

After that, I've been unable to reproduce the issue; including after deleting this virtualenv and recreating it from scratch (without the `zstd` package) via `./mach create-mach-environment`

I seem to have worked around this locally, possibly by installing the `zstd` package in my `.mozbuild/_virtualenvs/mach` directory, though I'm not entirely sure if that's what did it.

I don't know if these steps are advisable, but for the record, the steps that may've worked around this for me were:
```
cd /path/to/.mozbuild/_virtualenvs/mach
source ./bin/activate 
pip install zstd
```

After that, I was able to get through a bootstrap and I've been unable to reproduce the issue; including after deleting this virtualenv and recreating it from scratch (without the `zstd` package) via `./mach create-mach-environment`