gnu: shotwell: Update to 0.26.1.

* gnu/packages/gnome.scm (shotwell): Update to 0.26.1.
[inputs]: Add libgdata.

gnu: Add libgdata.

* gnu/packages/gnome.scm (libgdata): New variable.
* gnu/packages/patches/libgdata-fix-tests.patch,
gnu/packages/patches/libgdata-glib-duplicate-tests.patch: New files.
* gnu/local.mk (dist_patch_DATA): Add them.

Merge branch 'master' into staging

gnu: parallel: Update to 20170522.

* gnu/packages/parallel.scm (parallel): Update to 20170522.

gnu: Add emacs-direnv.

* gnu/packages/emacs.scm (emacs-direnv): New variable.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu: Add spectrwm.

* gnu/packages/wm.scm (spectrwm): New variable.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu: Add emacs-restclient.

* gnu/packages/emacs.scm (emacs-restclient): New variable.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

scripts: Set thread names.

This allows 'guix publish' threads as well as 'guix substitute' and
'guix offload' processes to be properly labeled in 'top', 'pstree', etc.

* guix/workers.scm (worker-thunk): Add #:thread-name parameter and honor it.
(make-pool): Likewise.
* guix/scripts/publish.scm (http-write): Add calls to 'set-thread-name'
in bodies of 'call-with-new-thread'.
(guix-publish): Call 'set-thread-name'.   Pass #:thread-name to 'make-pool'.
* guix/scripts/offload.scm (guix-offload): Call 'set-thread-name'.
* guix/scripts/substitute.scm (guix-substitute): Likewise.

syscalls: Add 'thread-name' and 'set-thread-name'.

* guix/build/syscalls.scm (PR_SET_NAME, PR_GET_NAME)
(%max-thread-name-length): New variables.
(%prctl, set-thread-name, thread-name): New procedures.
* tests/syscalls.scm ("set-thread-name"): New test.

gnu: certbot, python-acme: Update to 0.14.2.

* gnu/packages/tls.scm (certbot, python-acme, python2-acme): Update to 0.14.2.

gnu: rxvt-unicode: Disable an unwanted code execution vector.

* gnu/packages/patches/rxvt-unicode-escape-sequences.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/xdisorg.scm (rxvt-unicode)[source]: Use it.

gnu: synfigstudio: Fix patch name in 'gnu/local.mk'.

This is a followup to commit 2ac2b17251be51778963e6ced0b83e461d175d01.

* gnu/local.mk (dist_patch_DATA): Fix typo.

gnu: libtiff: Update replacement to 4.0.8 [security fixes].

See 'ChangeLog' in the source distribution for more information about
the bugs and security issues fixed in this release.

* gnu/packages/image.scm (libtiff)[replacement]: Replace with libtiff-4.0.8.
(libtiff/fixed): Replace with ...
(libtiff-4.0.8): New variable.
* gnu/packages/patches/libtiff-CVE-2017-7593.patch,
gnu/packages/patches/libtiff-CVE-2017-7594.patch,
gnu/packages/patches/libtiff-multiple-UBSAN-crashes.patch: Delete files.
* gnu/local.mk (dist_patch_DATA): Remove them.

gnu: offlineimap: Update to 7.1.1.

* gnu/packages/mail.scm (offlineimap): Update to 7.1.1.

gnu: font-bitstream-vera: Use 'font-build-system'.

* gnu/packages/fonts.scm (font-bitstream-vera): Switch to 'font-build-system'.

gnu: font-dejavu: Use 'font-build-system'.

* gnu/packages/fonts.scm (font-dejavu): Switch to 'font-build-system'.

gnu: font-ubuntu: Use 'font-build-system'.

* gnu/packages/fonts.scm (font-ubuntu): Switch to 'font-build-system'.

gnu: font-inconsolata: Use 'font-build-system'.

* gnu/packages/fonts.scm (font-inconsolata): Switch to 'font-build-system'.

build-system: Add 'font-build-system'.

* Makefile.am (MODULES): Add 'guix/build-system/font.scm' and
  'guix/build/font-build-system.scm'.
* guix/build-system/font.scm: New file.
* guix/build/font-build-system.scm: New file.
* doc/guix.texi (Build Systems): Add 'font-build-system'.

gnu: synfigstudio: Fix UI bug.

* gnu/packages/patches/synfigstudio-fix-ui-with-gtk3.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add patch.
* gnu/packages/animation.scm (synfigstudio)[source]: Apply patch.