Update all sources from freedesktop.org to use https

* gnu/packages/xorg.scm:
* gnu/packages/xdisorg.scm:
* gnu/packages/video.scm:
* gnu/packages/tls.scm:
* gnu/packages/python.scm:
* gnu/packages/pulseaudio.scm:
* gnu/packages/polkit.scm:
* gnu/packages/pdf.scm:
* gnu/packages/libcanberra.scm:
* gnu/packages/gtk.scm:
* gnu/packages/gstreamer.scm:
* gnu/packages/gnome.scm:
* gnu/packages/glib.scm:
* gnu/packages/ghostscript.scm:
* gnu/packages/freedesktop.scm:
* gnu/packages/fontutils.scm: Update all sources hosted on freedesktop
  to fetch tarballs via https.  freedesktop.org appears to have updated
  recently to redirect all http to https.  As an exception, we leave
  pkg-config like it is, because pkg-config is needed to build gnutls,
  and without gnutls we can't download https URLs.

gnu: python-pycairo: Define 'python2-variant'.

* gnu/packages/gtk.scm (python-pycairo)[properties]: New field.
(python2-pycairo): Use 'strip-python2-variant'.

gnu: Add murrine.

* gnu/packages/gtk.scm (murrine): New variable.

gnu: Add gtk-engines.

* gnu/packages/gtk.scm (gtk-engines): New variable.

gnu: gtksourceview: Update to 3.18.2.

* gnu/packages/gtk.scm (gtksourceview): Update to 3.18.2.

gnu: atkmm: Update to 2.24.2.

* gnu/packages/gtk.scm (atkmm): Update to 2.24.2.

gnu: harfbuzz: Update to 1.0.6 [fixes CVE-2016-2052].

* gnu/packages/gtk.scm (harfbuzz): Update to 1.0.6.

Merge branch 'master' into core-updates

gnu: gtk+: Add patch to support GUIX_GTK3_PATH.

* gnu/packages/patches/gtk3-respect-GUIX_GTK3_PATH: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/gtk.scm (gtk+) [source]: Add patch.
[native-search-paths]: Add search path for GUIX_GTK3_PATH.

gnu: gtk+-2: Add patch to support GUIX_GTK2_PATH.

* gnu/packages/patches/gtk2-respect-GUIX_GTK2_PATH: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/gtk.scm (gtk+-2) [source]: Add patch.
[native-search-paths]: Add search path for GUIX_GTK2_PATH.

Merge branch 'master' into core-updates

gnu: gdk-pixbuf: Update to 2.32.3. (fixes CVE-2015-4491)

* gnu/packages/gtk.scm (gdk-pixbuf): Update to 2.32.3.

gnu: python2-pygtk: Add "doc" output.

* gnu/packages/gtk.scm (python2-pygtk)[outputs]: New field.
[arguments]: Add 'set-gtk-doc-directory' phase.

gnu: python2-pygtk: Use 'modify-phases'.

* gnu/packages/gtk.scm (python2-pygtk)[arguments]: Use 'modify-phases'.

Merge branch 'master' into core-updates

gnu: Adjust formatting as recommended by 'guix lint'.

* gnu/packages/aidc.scm (barcode, qrencode),
  gnu/packages/bash.scm (bash, bash-completion),
  gnu/packages/busybox.scm (busybox),
  gnu/packages/cdrom.scm (cdparanoia),
  gnu/packages/cmake.scm (cmake),
  gnu/packages/conkeror.scm (conkeror),
  gnu/packages/cook.scm (cook),
  gnu/packages/curl.scm (curl),
  gnu/packages/docbook.scm (docbook-xsl),
  gnu/packages/enlightenment.scm (enlightenment),
  gnu/packages/games.scm (abbaye),
  gnu/packages/geeqie.scm (exiv2),
  gnu/packages/gimp.scm (gegl),
  gnu/packages/gl.scm (glu, freeglut, ftgl),
  gnu/packages/glib.scm (glib),
  gnu/packages/gnome.scm (orbit2, gconf, geocode-glib),
  gnu/packages/gstreamer.scm (gstreamer, gst-plugins-base),
  gnu/packages/linux.scm (util-linux),
  gnu/packages/lisp.scm (gcl, ecl),
  gnu/packages/maths.scm (gnuplot, hdf5),
  gnu/packages/ssh.scm (dropbear),
  gnu/packages/web.scm (json-c): Remove tabulations and trailing
  white spaces or reformat to fit within 80 columns.
* gnu/packages/audio.scm (aubio),
  gnu/packages/emacs.scm (emacs-s),
  gnu/packages/engineering.scm (geda-gaf),
  gnu/packages/games.scm (dosbox),
  gnu/packages/gnome.scm (gusb),
  gnu/packages/gtk.scm (gtk+),
  gnu/packages/guile.scm (guile-wisp),
  gnu/packages/hurd.scm (hurd-headers),
  gnu/packages/wm.scm (i3-wm): Adjust synopsis or description.

gnu: gtksourceview-2: Propagate input libxml2.

* gnu/packages/gtk.scm (gtksourceview-2): Move libxml2 to propagated
  inputs.

gnu: Add gtksourceview.

* gnu/packages/gtk.scm (gtksourceview): Rename to...
  (gtksourceview-2): ... this.
  (gtksourceview): Update to 3.18.1.
* gnu/packages/ocaml.scm (lablgtk)[inputs]: Replace "gtksourceview" with "gtksourceview-2".

Co-authored-by: 宋文武 <iyzsong@gmail.com>

Merge branch 'dbus-update'

gnu: ganv, pavucontrol, jalv: Fix build by compile with C++11.

* gnu/packages/audio.scm (jalv)[arguments],
  gnu/packages/gtk.scm (ganv)[arguments],
  gnu/packages/music.scm (non-sequencer)[arguments],
  gnu/packages/pulseaudio.scm (pavucontrol)[arguments]: Set
  'CXXFLAGS' to '-std=c++11'.