* gnu/system/vm.scm (system-qemu-image): Build a 'motd' and an 'issue' file. Pass 'unix-pam-service' that motd. Have /etc/issue point to the 'issue' file.
* gnu/packages/grub.scm (<menu-entry>, grub-configuration-file): Move to... * gnu/system/grub.scm: ... here. New file. * gnu/packages/linux.scm (<pam-service>, <pam-entry>, pam-service->configuration, pam-service->directory, %pam-other-services, unix-pam-service): Move to... * gnu/system/linux.scm: ... here. New file. * gnu/system/vm.scm (passwd-file): Move to... * gnu/system/shadow.scm: ... here. New file. * gnu-system.am (GNU_SYSTEM_MODULES): Add gnu/system/{grub,linux,shadow}.scm.