The update_file.py tool now preserves the end of line of the updated
file. Fix the "make regen-frozen" command: it no longer changes the
end of line of PCbuild/ files on Unix. Git changes the end of line
depending on the platform.
Frozen modules must be added to several files in order to work properly. Before this change this had to be done manually. Here we add a tool to generate the relevant lines in those files instead. This helps us avoid mistakes and omissions.
https://bugs.python.org/issue45019
