FTBFS with Python 3.12

[Aaron Rainbolt]

When building the abinit package on a system with Python 3.12 installed, the build fails with a "ModuleNotFoundError: No module named 'imp'" in fkiss/project.py. This file is used by abisrc.py, which is used as a critical part of the build configuration process, thus when this script fails, it takes down the whole build.

This bug is being tracked upstream at https://github.com/abinit/abinit/issues/69.

Steps to reproduce:

1. Configure your builder to enable `noble-proposed` and pin all packages from it. I'm doing this with a script as follows:

```
#!/bin/bash
echo "deb http://archive.ubuntu.com/ubuntu/ noble-proposed main universe restricted multiverse" >> /etc/apt/sources.list
echo "deb-src http://archive.ubuntu.com/ubuntu/ noble-proposed main universe restricted multiverse" >> /etc/apt/sources.list
echo "Package: *" > /etc/apt/preferences.d/99proposed
echo "Pin: release a=noble-proposed" >> /etc/apt/preferences.d/99proposed
echo "Pin-Priority: 900" >> /etc/apt/preferences.d/99proposed
```

This is then called in my .sbuildrc with the following config:

```
$external_commands = {
    "chroot-setup-commands" => [
        ['/repo/enableProposed.sh'],
    ],
};
```

2. Attempt to build abinit from source with this builder. The build will
fail and display failure output similar to the output in the upstream
bug report. You should be able to find the abisrc.stderr file inside the
build directory within your builder (find it with `find | grep stderr`)
and see that it has output similar to the output shown in the first
comment of the upstream bug report.