This means the package is usable as a library, which is useful when using the
procedures to send requests to the Guix Build Coordinator.
* gnu/packages/package-management.scm (guix-build-coordinator)[inputs]: Move
guile inputs to propagated inputs.
[propagated-inputs]: Receive some inputs.
* gnu/services/guix.scm (make-guix-build-coordinator-start-script): Adjust the
start script to include propagated inputs.