gnu: libgit2: Update to 0.26.0.

* gnu/packages/version-control.scm (libgit2): Update to 0.26.0.  Remove
"libgit2-use-after-free.patch".
* gnu/packages/patches/libgit2-use-after-free.patch: Remove.
* gnu/local.mk (dist_patch_DATA): Remove it.

gnu: efl: Add wayland support.

* gnu/packages/enlightenment.scm (efl)[inputs]: Add wayland-protocols.
Move mesa ...
[propagated-inputs]: ... to here. Add libinput, libxkbcommon, wayland.
[arguments]: Add flags to enable wayland, elput and drm.

gnu: gst-plugins-good: Update disable-failing-tests phase.

* gnu/packages/gstreamer.scm (gst-plugins-good)[arguments]: Change the
list of tests to disable during 'disable-failing-tests phase.

services: ntp: Use the NTP pool via the 'guix' zone.

* gnu/services/networking.scm (%ntp-servers): Use *.guix.pool.ntp.org.

gnu: automake: Add 1.15.1.

* gnu/packages/autotools.scm (automake/latest): New variable.

gnu: guix: Search .go files of dependencies in lib/guile/.

* gnu/packages/package-management.scm (guix)[arguments]: Add (srfi
srfi-26) to #:modules.  Introduce 'gopath', distinct from 'path'.

gnu: guix: Update snapshot.

* gnu/packages/package-management.scm (guix): Update to 228a398.

git-download: Remove call to 'canonicalize-path'.

* guix/git-download.scm (git-predicate): Remove call to
'canonicalize-path' since this could lead to discrepancies.  For
instance it broke 'make update-guix-package' since it passes a
non-canonical directory name.

services: openssh: Extensions provide extra authorized keys.

* gnu/services/ssh.scm (extend-openssh-authorized-keys): New procedure.
(openssh-service-type)[compose, extend]: New fields.
* doc/guix.texi (Networking Services): Document the extension.

services: openssh: Add 'authorized-keys' field.

* gnu/services/ssh.scm (<openssh-configuration>)[authorized-keys]: New
field.
(authorized-key-directory): New procedure.
(openssh-config-file): Honor 'authorized-keys'.
(openssh-activation): Use 'with-imported-modules'.  Make /etc/ssh
755.  Create /etc/ssh/authorized_keys.d.
* doc/guix.texi (Networking Services): Document it.

services: cuirass: Set 'GIT_SSL_CAINFO' and 'GIT_EXEC_PATH'.

Reported by Ricardo Wurmus.

* gnu/services/cuirass.scm (cuirass-shepherd-service): Pass
 #:environment-variables.

doc: Give an example of arguments for the 'run-vm.sh' script.

Suggested by Oleg Pykhalov <go.wigust@gmail.com>.

* doc/guix.texi (Invoking guix system): Give an example of passing
arguments to the 'run-vm.sh' script.

gnu: ffmpeg: Update to 3.3.3.

* gnu/packages/video.scm (ffmpeg): Update to 3.3.3.

gnu: qemu: Build with support for Linux AIO

Add libaio as an input, such that QEMU is built with support for Asynchronous
I/O (AIO).

* gnu/packages/virtualization.scm (qemu)[inputs]: Uncomment libaio.

services: Add memcached.

* gnu/services/databases.scm (memcached-service-type, %memcached-accounts):
  New variables.
  (<memcached-configuration>): New record type.
  (memcached-service-type): New procedures.
* gnu/tests/databases.scm: New file.
* doc/guix.texi (Database Services): Document the new memcached service.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add entry for tests/databases.scm.

gnu: Add memcached.

* gnu/packages/databases.scm (memcached): New variable.

gnu: retroarch: Update to 1.6.3.

* gnu/packages/games.scm (retroarch): Update to 1.6.3.

gnu: yosys: Add dependency on z3.

* gnu/packages/fpga.scm (yosys): Add z3 to propagated-inputs.

gnu: Add z3.

* gnu/packages/maths.scm (z3): New variable.

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

gnu: erlang: Fix man-pages search path of 'erl -man'.

* gnu/packages/patches/erlang-man-path.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/erlang.scm (erlang)[source]: Use it.

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