> Unfortunately, guile-email does not seem to pass its tests when built
> with Guile 3.

Oops, I totally forgot about this! Thanks for the reminder!

The issues were mostly minor issues to do with the test driver,
autotools use, etc. I have fixed them all now. Please check with the
latest commit on the master branch.

I guess you're only using a git checkout of guile-email. But anyway, I
will publish a new minor release of guile-email in a week.