Currently we freeze the 3 main import-related modules, as well as one module for testing.  Adding more modules or otherwise making any adjustments requires manually editing several files (frozen.c, Makefile.pre.in, ...).  Those files aren't particularly obvious and it's easy to miss one.  So it would be helpful to have a tool that generates the necessary lines in the relevant files, to avoid manual editing.

I'll be putting up a PR shortly.