Hey,

This has been on my todo list ever since the childhurd service came in
to existence. I spent some more time looking at it yesterday, and did
manage to get the agent working in a childhurd VM, at least somewhat.

Firstly, guile-lib needed tweaking so that it actually cross compiles,
I've sent a patch [1].

1: https://lists.gnu.org/archive/html/guile-devel/2021-02/msg00004.html

Adding the agent service also required this tweak [2].

2: https://issues.guix.gnu.org/46506

Then I faced two problems with the guix-build-coordinator
package. Firstly, wrap-program picks bash for Linux for the wrapper
script, which isn't very useful. I hacked around this by setting the
PATH such that it picked bash for the Hurd. In terms of properly fixing
this, I guess that needs to somehow be able to find the right bash, I'm
not sure how though?

The second issue is that I'm not sure capturing the build time
GUILE_LOAD_COMPILED_PATH doesn't seem to work, at least file says that
the .go files this contains are built for a 64-bit architecture. I
worked around this by constructing the GUILE_LOAD_COMPILED_PATH from the
inputs I knew should be on it. Maybe it should always have been done
this way, any ideas?

There's also one problem probably within the Guix Build Coordinator
itself, after doing a few builds, it will just stop. I've only seen this
behaviour on the Hurd, but I'm unsure how to debug it, any suggestions?
My only idea is add more logging.

Thanks,

Chris