* guix/build/linux-initrd.scm (boot-system): New procedure.
* gnu/system/linux-initrd.scm (qemu-initrd): Add keyword parameters
'guile-modules-in-chroot?' and 'mounts'. Change builder to simply
call 'boot-system'.
(gnu-system-initrd): Change to a simple call to 'qemu-initrd'.
* gnu/system/vm.scm (expression->derivation-in-linux-vm): Call
'qemu-initrd' with #:guile-modules-in-chroot?.
* gnu/packages/linux-initrd.scm (qemu-initrd): Add (guix build utils) to
#:modules, and use it. Copy .scm and .go files to /root.
* guix/build/linux-initrd.scm (bind-mount): New procedure.
* gnu/packages/linux-initrd.scm (qemu-initrd): Add #:modules argument.
Factorize and move some of the code to...
* guix/build/linux-initrd.scm: ... here. New file.
* Makefile.am (MODULES): Add it.