gnu: Add zerofree.

* gnu/packages/linux.scm (zerofree): New variable.

gnu: e2fsprogs: Install libext2fs.

* gnu/packages/linux.scm (e2fsprogs)[source]: Add 'snippet'.
  [arguments]: Add --enable-elf-shlibs to #:configure-flags.
  Add #:make-flags.

gnu: Add GLEW.

* gnu/packages/gl.scm (glew): New variable.

services: user-processes: Really honor the grace delay.

* gnu/services/base.scm (user-processes-service): Change #:grace-delay
  default value to 4.  Define 'sleep*' and use it.

system: Add iw to '%base-packages'.

* gnu/system.scm (%base-packages): Add IW.

gnu: wireless-tools: Describe it as deprecated.

* gnu/packages/linux.scm (wireless-tools)[description]: Explain that it
  is deprecated in favor of 'iw'.

gnu: guix: Update snapshot.

* gnu/packages/package-management.scm (guix-devel): Update snapshot.
  Remove now-unneeded sub-module stuff in the 'bootstrap' phase.

gnu: Add QPDF.

* gnu/packages/pdf.scm (qpdf): New variable.

tests: Properly synchronize threads in the 'home-page' lint tests.

* tests/lint.scm (%http-server-lock, %http-server-ready): New
  variables.
  (http-open): New procedure.
  (stub-http-server): Use it.
  (call-with-http-server): Wrap body in 'with-mutex'.  Call
  'wait-condition-variable' after 'make-thread'.

doc: Change some occurrences of "the GNU system" to "Guixotic".

* doc/guix.texi (GNU Distribution): Explain what "Guixotic" is.
  (System Installation): Replace "the GNU system" by "Guixotic".
  (System Configuration): Likewise.
  (Invoking guix system): Likewise.

build/glib-or-gtk-build-system: Fix 'generate-icon-cache'.

Reported by Mark H Weaver <mhw@netris.org>

* guix/build/glib-or-gtk-build-system.scm (generate-icon-cache): Add check for
  existence of icons directory.

gnu: Add iw.

* gnu/packages/linux.scm (iw): New variable.

gnu: libnl: Update to 3.2.25.

* gnu/packages/linux.scm (libnl): Update to 3.2.25.

monads: Remove 'derivation-expression'.

* guix/monads.scm (lower-inputs, derivation-expression): Remove.
* tests/monads.scm (derivation-expression, "mlet* +
  derivation-expression"): Remove.

monads: Rewrite 'text-file*' using gexps.

* guix/monads.scm (text-file*): Move to...
* guix/gexp.scm (text-file*): ... here.  Rewrite using gexps.
* tests/monads.scm ("text-file*"): Move to...
* tests/gexp.scm ("text-file*"): ... here.

services: user-processes: Write debugging messages to the output port.

* gnu/services/base.scm (user-processes-service): Write "sending all
  processes..." message to the current output port, not to /dev/console.

gnu: Move xlockmore to (gnu packages xdisorg).

* gnu/packages/xlockmore.scm: Remove.
* gnu/packages/xdisorg.scm (xlockmore): New variable, from
  xlockmore.scm.
* gnu-system.am (GNU_SYSTEM_MODULES): Remove xlockmore.scm.

gnu: xlockmore: Update to 5.45.

* gnu/packages/xlockmore.scm (xlockmore): Update to 5.45.
  [arguments]: Add #:configure-flags.

gnu: evince: Add inputs.

* gnu/packages/gnome.scm (evince): Add 'dconf' and 'libcanberra' inputs.
  Remove custom phase 'set-mime-search-path which is now handled by
  glib-or-gtk-build-system.

gnu: libcanberra: Add default sounds support.

* gnu/packages/libcanberra.scm (libcanberra): Add input
  'sound-theme-freedesktop'.  Add "libcanberra-sound-theme-freedesktop.patch"
  and related phase 'patch-default-sounds-directory to patch the default
  sounds directory.