vm: Disable swap devices in virtualized OSes.

* gnu/system/vm.scm (virtualized-operating-system): Add 'swap-devices'
  field.

gnu: sdl: Fix home page URLs.

* gnu/packages/sdl.scm (sdl-image, sdl-mixer, sdl-net, sdl-ttf): Prepend
  "http://" to 'home-page'.

gnu: calcurse: Update to 3.2.1.

* gnu/packages/calcurse.scm (calcurse): Update to 3.2.1.

gnu: freeimage: Remove MIPS from supported-systems.

* gnu/packages/image.scm (freeimage): Drop support for "mips64el-linux".

gnu: phonon: Update to 4.8.2.

* gnu/packages/kde.scm (phonon): Update to 4.8.2.

gnu: xf86-video-ati: Update to 6.14.6.

* gnu/packages/xorg.scm (xf86-video-ati): Update to 6.14.6 to circumvent
    build failures.

tests: When a store item is to be deleted, make it statistically unique.

Fixes <http://bugs.gnu.org/18935>.
Reported by Mark H Weaver <mhw@netris.org>.

Previously, if tests/nar.scm ran concurrently with tests/gexp.scm, the
store item "foo" containing the string "Hello, world!" could be
deleted (via 'delete-paths') from the tests/nar.scm daemon while the
tests/gexp.scm daemon would still consider it live.

* tests/nar.scm ("restore-file-set (missing signature)"):
  Use (random-text) rather than "Hello, world!", to avoid concurrent
  deletion of store item "foo" used in tests/gexp.scm.

store: Invalidate caches once GC has run.

* guix/store.scm (run-gc): Add calls to 'hash-clear!'.
* tests/store.scm ("add-text-to-store vs. delete-paths",
  "add-to-store vs. delete-paths"): New tests.

gnu: qt: Update to 5.3.2.

* gnu/packages/qt.scm (qt): Update to 5.3.2. Drop configure flag
    -no-neon, which is not supported any more.

gnu: gcc-4.9: Update to 4.9.2.

* gnu/packages/gcc.scm (gcc-4.9): Update to 4.9.2.

gnu: Add GNU adns.

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

gnu: evince: Use 'glib-or-gtk-build-system'.

* gnu/packages/gnome.scm (evince)[build-system]: Switch to
  GLIB-OR-GTK-BUILD-SYSTEM.

gnu: gdb: Do not install libopcodes and libbfd.

* gnu/packages/gdb.scm (gdb)[arguments]: Add 'post-install' phase.

gnu: gdb: Update to 7.8.1.

* gnu/packages/gdb.scm (gdb): Update to 7.8.1.

gnu: Add docbook-xml-4.2

* gnu/packages/docbook.scm (docbook-xml-4.2): New variable.

gnu: Add gnome-themes-standard.

* gnu/packages/gnome.scm (gnome-themes-standard): New variable.

gnu: librsvg: Generate complete loaders.cache including support for SVG.

* gnu/packages/gnome.scm (librsvg): Add 'generate-full-cache phase.

gnu: qt: Explicitly link with the dbus library.

* gnu/packages/qt.scm (qt, qt-4): Add a configure flag to link explicitly
    with dbus.

doc: emacs: Fix titles of the printed manuals.

* doc/emacs.texi: Use the proper names of the printed manuals in the
  cross references.

emacs: Add interface for comparing generations.

Suggested by Ludovic Courtès.

* doc/emacs.texi (Emacs List buffer): Document new key bindings.
* emacs/guix-base.el (guix-generation-packages-buffer-name-function,
  guix-generation-packages-update-buffer, guix-output-name-width): New
  variables.
  (guix-generation-file, guix-manifest-file, guix-generation-packages,
  guix-generation-packages-buffer-name-default,
  guix-generation-packages-buffer-name-long,
  guix-generation-packages-buffer-name, guix-generation-packages-buffer,
  guix-generation-insert-package, guix-generation-insert-packages,
  guix-profile-generation-manifest-file,
  guix-profile-generation-packages-buffer): New procedures.
* emacs/guix-list.el: Add key bindings for comparing generations.
  (guix-generation-list-generations-to-compare,
  guix-generation-list-show-added-packages,
  guix-generation-list-show-removed-packages, guix-generation-list-compare,
  guix-generation-list-ediff-manifests, guix-generation-list-diff-manifests,
  guix-generation-list-ediff-packages, guix-generation-list-diff-packages,
  guix-generation-list-ediff, guix-generation-list-diff): New procedures.
* emacs/guix-messages.el (guix-messages): Add 'generation-diff' search type.
  (guix-message-outputs-by-diff): New procedure.
* emacs/guix-utils.el (guix-diff-switches): New variable.
  (guix-diff): New procedure.
* emacs/guix-main.scm (package/output-sexps): Handle 'generation-diff' search
  type.
  (manifest-entry->package-specification,
  manifest-entries->package-specifications, generation-package-specifications,
  generation-package-specifications+paths, generation-difference): New
  procedures.