The default value of the argument REGISTER-CLOSURE? of the ISO9660-IMAGE,
QEMU-IMAGE and SYSTEM-DOCKER-IMAGE procedures can be computed automatically,
since the operating-system definition is available in its context. When the
operating-system definition does not contain the GUIX-SERVICE-TYPE, do not
register the closure in the database of Guix, as it takes time and doesn't
serve a purpose.
* gnu/system/vm.scm (has-guix-service-type): Add predicate.
(iso9660-image)[register-closures?]: Use it to compute the argument's default
value.
(qemu-image)[register-closures?]: Likewise, and update docstring.
(system-docker-image)[register-closures?]: Likewise.
(system-disk-image): Do not explicit a value for the REGISTER-CLOSURES?
argument of the ISO9660-IMAGE and QEMU-IMAGE procedure calls, so that its
default value is used instead.
* guix/scripts/system.scm (system-derivation-for-action): Do not explicit a
value for the REGISTER-CLOSURES? argument of the SYSTEM-DOCKER-IMAGE
procedure call, so that its default value is used instead.