* gnu/services/virtualization.scm (initialize-hurd-vm-substitutes)
(hurd-vm-activation): New procedures.
(hurd-vm-service-type)[extensions]: Add ACTIVATION-SERVICE-TYPE
extension.
* doc/guix.texi (Transparent Emulation with QEMU): Mention GNU/Hurd.
(The Hurd in a Virtual Machine): Explain which files are automatically
installed and mention offloading.