The `set-root-password` command sets up an alternate mount namespace
with a writable `/etc` directory and then runs `passwd` in it. This
allows `passwd` to create its lock files and backup files, without
requiring that the real `/etc` to be mutable. After `passwd` finishes
and has updated its private copy of `/etc/shadow`, the script rewrites
the real one with its contents.
In effort to support different builds of Aimee OS using the same
scripts, without necessarily having to fork this repository, the build
system now supports a `CONFIGDIR` setting. When this variable is set,
files defining the target environment, such as the lists of packages to
install, the kernel configuration, the Portage configuration, etc. are
found in the path it specifes.
The reference build, for the Home Assistant Yellow board, is configured
in the `yellow` directory. To build it, run:
```sh
CONFIGDIR=yellow ./vm-build.sh
```