services: Create /var/log upon activation.

When launching a container created with guix system container, the
attempt to create /var/log/wtmp would fail, as /var/log did not exist.

* gnu/services.scm (activation-script): Create /var/log

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

services: Add exim-service-type.

* gnu/services/mail.scm (<exim-configuration>): New record type.
(exim-computed-config-file, exim-shepherd-service, exim-activation, exim-etc,
exim-profile): New procedures.
(exim-service-type, %exim-accounts): New variables.
* doc/guix.text (Mail Services): Document it.

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

gnu: hmmer: Build reproducibly.

* gnu/packages/patches/hmmer-remove-cpu-specificity.patch: New file.
* gnu/packages/bioinformatics.scm (hmmer): Use it.

gnu: Add sambamba.

* gnu/packages/bioinformatics.scm (htslib-for-sambamba, sambamba): New
variables.

gnu: pidgin: Update to 2.12.0 [fixes CVE-2017-2640].

* gnu/packages/messaging.scm (pidgin): Update to 2.12.0.

gnu: neomutt: Configure with 'lmdb' and 'kyotocabinet'.

* gnu/packages/mail.scm (neomutt)[configure]: Add '--with-kyotocabinet'
and '--with-lmdb'.
[inputs]: Add 'lmdb' and 'kyotocabinet'.

Signed-off-by: Kei Kebreau <kei@openmailbox.org>

gnu: neomutt: Update to 20170306.

* gnu/packages/mail.scm (neomutt): Update to 20170306.

Signed-off-by: Kei Kebreau <kei@openmailbox.org>

Revert "gnu: neomutt: Configure with 'lmdb' and 'tokyocabinet'."

'kyotocabinet' is more current than tokyocabinet in development
and supported in neomutt aswell.

This reverts commit ef91e2b964ec0952698dd1bf7daf76624fed2145.

Signed-off-by: Kei Kebreau <kei@openmailbox.org>

gnu: hiawatha: Adjust description.

* gnu/packages/web.scm (hiawatha)[description]: Adjust it.

Signed-off-by: Kei Kebreau <kei@openmailbox.org>

gnu: Add font-tamzen.

* gnu/packages/fonts.scm (font-tamzen): New variable.

Signed-off-by: Kei Kebreau <kei@openmailbox.org>

gnu: btrfs-progs/static: Correct description.

* gnu/packages/linux.scm (btrfs-progs/static)[description]: Use the correct
name of the btrfs-progs package and @command{} mark-up.

gnu: btrfs-progs: Update to 4.10.

* gnu/packages/linux.scm (btrfs-progs): Update to 4.10.

gnu: ibus-anthy: Update to 1.5.9.

* gnu/packages/ibus.scm (ibus-anthy): Update to 1.5.9.

gnu: ibus: Update to 1.5.15.

* gnu/packages/ibus.scm (ibus): Update to 1.5.15.

gnu: pius: Update to 2.2.4.

* gnu/packages/gnupg.scm (pius): Update to 2.2.4.

gnu: youtube-dl: Update to 2017.03.07.

* gnu/packages/video.scm (youtube-dl): Update to 2017.03.07.

gnu: graphicsmagick: Build with 16 bit quantum depth.

Octave requires graphicsmagick to be built with 16 bit quantum depth.

* gnu/packages/imagemagick.scm (graphicsmagick)[arguments]: Add
"--with-quantum-depth=16" and "--enable-quantum-library-names"
to #:configure-flags.

Signed-off-by: Leo Famulari <leo@famulari.name>

gnu: octave: Build with curl and graphicsmagick.

* gnu/packages/maths.scm (octave)[inputs]: Add curl and graphicsmagick.

Signed-off-by: Leo Famulari <leo@famulari.name>

gnu: xf86-input-libinput: Update to 0.25.0.

* gnu/packages/xorg.scm (xf86-input-libinput): Update to 0.25.0.

gnu: Add python2-larch.

* gnu/packages/python.scm (python2-larch): New variable.

Signed-off-by: Marius Bakke <mbakke@fastmail.com>