* gnu/build/vm.scm (<partition>): New record type.
(fold2): New procedure.
(initialize-partition-table): Remove #:bootable? and
'partition-size' parameters. Add 'partitions' parameter. Invoke 'parted'
with '--script'.
(initialize-root-partition): Remove.
(initialize-partition, root-partition-initializer): New procedures.
(initialize-hard-disk): Remove #:system-directory, #:disk-image-size,
#:file-system-type, #:file-system-label, #:closures, #:copy-closures?,
#:bootable?, and #:register-closures? parameters. Add #:partitions.
Rewrite to use 'initialize-partition' for each item of PARTITIONS.
* gnu/system/vm.scm (expression->derivation-in-linux-vm): Add (guix records)
to #:modules default value.
(qemu-image): Adjust accordingly.