gnu: qt-4: Upgrade to 4.8.6.

* gnu/packages/qt.scm (qt-4): Upgrade to 4.8.6.

gnu: qt-4: Enable session management by adding libsm as an input.

* gnu/packages/qt.scm (qt-4): Add input qt-4.

vm: Pass '-serial stdio' in the run-vm.sh.

* gnu/system/vm.scm (system-qemu-image/shared-store-script): Add
  '-serial stdio'.

system: Move skeleton code to (gnu system shadow).

* gnu/system.scm (default-skeletons, skeleton-directory): Move to...
* gnu/system/shadow.scm: ... here.

doc: Improve debugging file documentation.

* doc/guix.texi (Installing Debugging Files): Add @cindex.  Remove
  unneeded '-i' in example.  Mention source code an 'directory'.  Link
  to "Build Systems" instead of "Defining Packages".

system: Add skeleton '.gdbinit'.

* gnu/system.scm (default-skeletons): Add .gdbinit.

gnu: openmpi: Use our hwloc.

* gnu/packages/mpi.scm (hwloc): Propagate numactl.
  (openmpi)[inputs]: Add hwloc.
  [native-inputs]: Add pkg-config.
  [argument]: Add hwloc configure flags.

gnu: Add babl.

* gnu/packages/gimp.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.

system: Populate /etc/skel.

* gnu/system.scm (<operating-system>)[skeletons]: New field.
  (default-skeletons, skeleton-directory): New procedures.
  (etc-directory): Add #:skeletons parameter.  Call
  'skeleton-directory', and produce the 'skel' sub-directory.
  (operating-system-etc-directory): Pass #:skeletons to
  'etc-directory'.

doc: Add example for --search.

* doc/guix.texi (Invoking guix package): Add LGPLv3 example.

gnu: perl-tk: Patch for i686

* gnu/packages/patches/perl-tk-x11-discover.patch: New patch.
* gnu-system.am [dist_patch_DATA]: Add it.
* gnu/packages/tcl.scm (perl-tk)[origin]: Use it.

system: Make accounts and groups at activation time.

* gnu/services/base.scm (guix-build-accounts): Remove #:gid parameter;
  add #:group.  Remove 'password' and 'gid' fields in 'user-account'
  form, and add 'group'.
  (guix-service): Remove #:build-user-gid parameter.  Remove 'id' field
  in 'user-group' form.
* gnu/system.scm (etc-directory): Remove #:groups and #:accounts.  No
  longer produce files "passwd", "shadow", and "group".  Adjust caller
  accordingly.
  (%root-account): New variable.
  (operating-system-accounts): Add 'users' variable.  Add %ROOT-ACCOUNT
  only of 'operating-system-users' doesn't already contain a root
  account.
  (user-group->gexp, user-account->gexp): New procedures.
  (operating-system-boot-script): Add calls to 'setenv' and
  'activate-users+groups' in gexp.
* gnu/system/linux.scm (base-pam-services): Add PAM services for
  "user{add,del,mode}" and "group{add,del,mod}".
* gnu/system/shadow.scm (<user-account>)[gid]: Rename to...
  [group]: ... this.
  [supplementary-groups]: New field.
  [uid, password]: Default to #f.
  (<user-group>)[id]: Default to #f.
  (group-file, passwd-file): Remove.
* gnu/system/vm.scm (operating-system-default-contents)[user-directories]:
  Remove.  Add "/home" to the directives.
* guix/build/activation.scm (add-group, add-user,
  activate-users+groups): New procedures.

services: xorg: Fix harmless typo in slim.cfg.

* gnu/services/xorg.scm (slim-service): Add missing whitespace in
  XINITRC invocation.

gnu: pspp: Upgrade to 0.8.3

* gnu/packages/maths.scm (pspp): Update to 0.8.3.

doc: Mention upgrades that trigger a lot of rebuilds.

* HACKING (Commit Access): Mention upgrades that trigger a lot rebuilds.

doc: Add a section on perl modules in the packaging guidelines.

* doc/guix.texi (Perl modules): New section explaining the naming of perl
    modules.

vm: Fix recently-introduced regression in 'operating-system-services' use.

* gnu/system/vm.scm (operating-system-build-gid): Adjust to new return
  type of 'operating-system-services' introduced in 217a5b8.

services: Add 'file-system-service'.

* gnu/services/base.scm (file-system-service): New procedure.
  (user-processes-service): Add 'requirements' parameter.
* gnu/services/dmd.scm (dmd-configuration-file): Use (guix build
  linux-initrd).
* guix/build/linux-initrd.scm (guix): Export 'check-file-system'.
* gnu/system.scm (file-union): New procedure.
  (essential-services): Use it.  Add that to the returned list.

services: Use (guix build syscalls) instead of util-linux.

* gnu/services/dmd.scm (dmd-configuration-file): Add derivations for
  the (guix build syscalls) module, and add that to the load path of
  dmd.conf.
* gnu/services/base.scm (root-file-system-service): Rewrite using the
  'sync' and 'mount' procedures.

Add (guix build syscalls).

* guix/build/syscalls.scm, tests/syscalls.scm: New files.
* Makefile.am (MODULES): Add guix/build/syscalls.scm.
  (SCM_TESTS): Add tests/syscalls.scm.
* guix/utils.scm (%libc-errno-pointer, errno): Remove; take from (guix
  build syscalls).