* gnu/build/linux-boot.scm (boot-system): Add #:pre-mount parameter and
honor it.
* gnu/system/linux-initrd.scm (base-initrd): Add #:mapped-devices
parameter. Add 'device-mapping-commands' variable, and use it to
build the #:pre-mount argument of 'boot-system'.
* gnu/system.scm (mapped-device-user,
operating-system-user-mapped-devices,
operating-system-boot-mapped-devices): New procedures.
(device-mapping-services): Use 'operating-system-user-mapped-devices'
instead of 'operating-system-mapped-devices'.
(operating-system-initrd-file): Call the initrd with #:mapped-devices.
de1c158f32