On 09-10-2022 06:02, 'Brendan Tildesley wrote:
> +                   (string-append "DESTDIR=" #$output)

Guix doesn't do staged installation. The variable you need to set is 
PREFIX instead, see 
<https://www.gnu.org/prep/standards/html_node/DESTDIR.html>.

Otherwise the definition looks reasonable.

Greetings,
Maxime.