Merge branch 'master' into core-updates

install: Use a low-memory nscd caching policy.

* gnu/system/install.scm (%nscd-minimal-caches): New variable.
  (installation-services): Use as 'nscd-service' argument.

Merge branch 'master' into 'core-updates'.

system: Change "en_US.UTF-8" to "en_US.utf8".

* build-aux/hydra/demo-os.scm (locale): Change to "en_US.utf8".
* gnu/system/install.scm (installation-os)[locale]: Ditto.

install: Add wpa-supplicant to the image.

Reported by Amirouche Boubekki <amirouche.boubekki@gmail.com>.

* gnu/system/install.scm (installation-os)[packages]: Add
  WPA-SUPPLICANT.

install: Add Cryptsetup to the image.

Reported by Nikita Karetnikov.

* gnu/system/install.scm (installation-os)[packages]: Add CRYPTSETUP.
* doc/guix.texi (System Installation): Mention it.

services: Add 'auto-start?' field to <service>.

* gnu/services.scm (<service>)[auto-start?]: New field.
* gnu/services/dmd.scm (dmd-configuration-file): Honor it.
* gnu/system/install.scm (cow-store-service): Add 'auto-start?' field.

services: Add 'user-unmount-service' as an essential service.

* gnu/services/base.scm (user-unmount-service): New procedure.
* gnu/system.scm (essential-services): Use it.
* gnu/system/install.scm (cow-store-service): Mention it in comment.

install: Add GRUB to the set of global packages.

* gnu/system/install.scm (installation-os)[packages]: Add GRUB.

Merge branch 'master' into core-updates

install: Add a configuration template to the image.

* gnu/system/os-config.tmpl: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it
* gnu/system/install.scm (configuration-template-service): New
  procedure.
  (installation-services): Call it.
* doc/guix.texi (System Installation): Mention
  configuration-template.scm, and @include gnu/system/os-config.tmpl.

install: Add a service to back the store with the target disk.

Fixes <http://bugs.gnu.org/18061>.
Reported by Adam Pribyl <pribyl@lowlevel.cz>.

* gnu/services/dmd.scm (dmd-configuration-file)[config]: Import (guix
  build utils).
* gnu/system/install.scm (make-cow-store, cow-store-service): New
  procedures.
  (installation-services): Use it.
  (%backing-directory): New variable.
* doc/guix.texi (System Installation): Add the 'deco start cow-store
  /mnt' phase.

system: Add '%devtmpfs-file-system' for udev, and '%base-file-systems'.

Suggested by Adam Pribyl <pribyl@lowlevel.cz>.

* gnu/services/base.scm (udev-service)[requirement]: Add
  'file-system-/dev'.
* gnu/system/file-systems.scm (%devtmpfs-file-system,
  %base-file-systems): New variables.
* gnu/system/install.scm (installation-services)[file-systems]: Use
  %base-file-systems.
* build-aux/hydra/demo-os.scm (file-systems): Likewise.
* doc/guix.texi (System Installation): Show %BASE-FILE-SYSTEMS in the
  example.
  (Using the Configuration System): Likewise.
  (File Systems): Document %base-file-systems, %devtmpfs-file-system,
  %binary-format-file-system, and %fuse-control-file-system.

install: Add wireless-tools package.

* gnu/system/install.scm (installation-os): Add wireless-tools to packages.

install: Show the "System Installation" node.

* gnu/system/install.scm (log-to-info): Go to the new 'System
  Installation' node.

services: Add 'console-font-service'.

* gnu/services/base.scm (unicode-start, console-font-service): New
  procedures.
  (%base-services): Call 'console-font-service' for TTY1 to TTY6.
* gnu/system/install.scm (installation-services): Add comment about the
  console font.  Call 'console-font-service' for TTY1 to TTY6.

install: Remove GNU fdisk from the image.

* gnu/system/install.scm (installation-os): Remove FDISK.

install: Use udev.

* gnu/system/install.scm (installation-services): Call 'udev-service'.

system: Use the default 'groups' field.

* gnu/system/install.scm (installation-os): Remove 'groups' field.
* build-aux/hydra/demo-os.scm: Likewise.

system: Remove useless 'members' field of 'user-group'.

* gnu/system/shadow.scm (<user-group>)[members]: Remove field.
* gnu/system/install.scm (installation-os)[users]: Remove 'members'
  fields.  Use 'supplementary-groups' for 'guest'.
* build-aux/hydra/demo-os.scm (users): Likewise.
* gnu/services/base.scm (guix-service): Remove 'members' field.