doc: Merge the type, variable, and function indices.

* doc/guix.texi (Function Index): Rename to...
  (Programming Index): ... this.  Merge the type, variable, and function
  indices.

system: Add 'file-system' decl. for /dev/pts, and use the right options.

Fixes <http://bugs.gnu.org/18081>.

* gnu/system/file-systems.scm (%devtmpfs-file-system): Add
  'needed-for-boot?' field.
  (%tty-gid, %pseudo-terminal-file-system): New variables.
  (%base-file-systems): Add %PSEUDO-TERMINAL-FILE-SYSTEM.
* gnu/services/base.scm (udev-service): Remove dependency on
  'file-system-/dev'.
* gnu/system/shadow.scm (%base-groups): Add 'id' field for group 'tty'.
* guix/build/linux-initrd.scm (boot-system): Remove 'mount' call for
  /dev/pts.
* doc/guix.texi (File Systems): Add %pseudo-terminal-file-system.

system: Add 'create-mount-point?' file system option.

* gnu/system/file-systems.scm (<file-system>)[create-mount-point?]: New
  field.
* gnu/services/base.scm (file-system-service): Add #:create-mount-point?
  parameter and honor it.
* gnu/system.scm (other-file-system-services): Update
  'file-system-service' call accordingly.
* doc/guix.texi (File Systems): Document it.

Require only lower gettext version.

* configure.ac: Change back to requiring gettext at least 0.18.1, partially
    reverting commit ee76417.

Thank Adam.

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.

doc: Fix typo.

* doc/guix.texi (System Installation): s/are/is/.

Add comments about global memoization.

* guix/build-system/gnu.scm (standard-inputs): Add comment about
  misplaced memoization.
* guix/packages.scm (cache): Likewise.

services: Allow 'check-file-system' to work for non-boot-time file systems.

* gnu/services/base.scm (file-system-service)[start]: Set $PATH so that
  fsck.* can be found.  Reported by "DusXMT".

Update 'NEWS'.

guix package: add a "show" option.

* doc/guix.texi: Update the documentation.
* guix/scripts/package.scm: Add a "show" option.
* tests/guix-package.sh: Add a test for the "show" option.

ui: add the "dependencies" field to package->recutils:

* guix/ui.scm (package->recutils): Print the dependencies of the package.

nls: Add Hungarian translation.

build: Fix typo that would lead to hitting the socket name length limit.

* tests/guix-register.sh: Remove redundant $new_store in $NIX_STATE_DIR,
  introduced in 689142cd ("guix-register: Add '--state-directory'
  parameter.")  Reported by Eric Bavier <ericbavier@gmail.com> and
  Alen Skondro <askondro@gmail.com>.

doc: Show output of 'guix refresh --list-dependent' example.

* doc/guix.texi (Invoking guix refresh): Show example output of the
  command.

guix refresh: Use (ice-9 format).

* guix/scripts/refresh.scm: Use (ice-9 format).

guix system: Factorize 'copy-closure'.

* guix/scripts/system.scm (copy-closure): Rename to...
  (copy-item): ... this.
  (copy-closure): New procedure.
  (install): Use it, and remove redundant code.

gnu: ffmpeg: Remove --disable-vis.

* gnu/packages/video.scm (ffmpeg): Remove --disable-vis.

gnu: wpa-supplicant: Update to 2.2.

* gnu/packages/admin.scm (wpa-supplicant): Update to version 2.2.

gnu: sudo: Update to 1.8.10p3.

* gnu/packages/admin.scm (sudo): Update to version 1.8.10p3.