Hi,

I've installed guix-system and did some further testing:

The package seems to work just fine when properly installing jack2,
pipewire (pw-jack) or jack on guix-system (and Fedora). It's possible to
put jack (v1) in the propagated inputs, but that's not that elegant I
suppose. Furthermore all the audio packages I could find in guix include
jack in the same way, at build time and not as a propagated input.

I cannot test this with actual midi hardware, only with the
midiout.open_virtual_port method. But for my use case (using the OLA
suite), the library works fine, even when using real DMX controller
hardware.

So after testing and configuring my system properly, I have found no reason
for a revised patch. If you or someone else wants to take a look at this
patch, please do.

Thanks.

-- 
Kind regards,

Rick Huijzer