> Do I understand right that dist_msi builds a database of the files, and
> that the identifiers could be named differently than the filenames
> themselves, as long as they are unique ?

Correct. As a design objective, I try to use identifiers close to the
file names, to simplify debugging of the MSI file (Microsoft itself
typically uses UUIDs instead).

In short, just make make_id generate valid identifiers. An algorithm
on top of that will make them unique in case of conflicts.

Regards,
Martin