install --with-version?

[pelzflorian (Florian Pelz)]

Hello!

I wanted to install biber 2.10 but Guix has and never had a package
for it (I think).  So I think of rewriting the existing package.

I see no --with-version option for `guix build`.

I tried

guix environment --ad-hoc -e '(begin (use-modules (guix packages) (gnu packages 
tex)) (package (inherit biber) (version "2.10")))'

but it still uses the source for the current biber 2.12 instead of
biber 2.10.  I suppose Guix’ record implementation is “hygienic” and
never refers to a changed version.

What to do?

Regards,
Florian