ERROR: Unknown target name 'arm-softmmu'

While setting up the development environment, ([following this tutorial](https://jsandler18.github.io/tutorial/dev-env.html)) when I run `./configure --target-list=arm-softmmu,arm-linux-user` to configure QEMU, I get the following error:
```
ERROR: Unknown target name 'arm-softmmu'
```

*Ubuntu 20.04*