* gnu/system/vm.scm (qemu-image): Rename #:inputs-to-copy to #:inputs,
and #:initialize-store? to #:register-closures?. Add #:copy-inputs?.
Adjust build gexp accordingly.
(system-qemu-image): Remove #:initialize-store? argument and add
#:copy-inputs?.
(system-qemu-image/shared-store): Add #:inputs, #:register-closures?,
and #:copy-inputs? arguments.
* guix/build/vm.scm (register-closure): New procedure.
(MS_BIND): New variable.
(initialize-hard-disk): Rename #:initialize-store? to
#:register-closures?, #:closures-to-copy to #:closures, and add
#:copy-closures?.
Add 'target-directory' and 'target-store' variables.
Call 'populate-store' only when COPY-CLOSURES?.
Bind-mount the store to TARGET-STORE when REGISTER-CLOSURES? and not
COPY-CLOSURES?. Add call to 'register-closure'.