mutt builds to fail on a barebones sytem

[Carlos Sánchez de La Lama]

Hi all,

in my new system (almost identical to the barebones template), mutt does
not build:

--8<---------------cut here---------------start------------->8---
$ guix package -i mutt

...

chgrp: invalid group: ‘mail’
Can't fix mutt_dotlock's permissions!  This is required to lockmailboxes in the 
mail spool directory.
Makefile:1337: recipe for target 'install-exec-hook' failed
--8<---------------cut here---------------end--------------->8---

I have tried looking for a module which creates the mail group but I
have not found it. Do I need to add "mail" to groups field on system
definition? Or is it somehow automatically added it mutt is added at the
system level?

Thanks!

Carlos