gnu: Add r-mass.

* gnu/packages/statistics.scm (r-mass): New variable.

gnu: Add r-boot.

* gnu/packages/statistics.scm (r-boot): New variable.

doc: Really document 'guix pack --format'.

* doc/guix.texi (Invoking guix pack): Properly document --format.

gnu: youtube-dl: Update to 2017.03.16.

* gnu/packages/video.scm (youtube-dl): Update to 2017.03.16.

gnu: asciidoc: Use local docbook-xml package.

* gnu/packages/documentation.scm (asciidoc)[inputs]: Add docbook-xml.
[arguments]: Add 'make-local-docbook-xml' phase.

gnu: Add knot.

* gnu/packages/dns.scm (knot): New variable.

gnu: Add liburcu.

* gnu/packages/datastructures.scm (liburcu): New variable.

gnu: dns: Fix typo and use @dfn in descriptions.

* gnu/packages/dns.scm (bind)[description]: Use @dfn to expand acronyms.
(yadifa)[description]: Likewise, and fix a typo.

gnu: linux-libre: Update to 4.10.3.

* gnu/packages/linux.scm (%linux-libre-version): Update to 4.10.3.
(%linux-libre-hash): Update hash.

gnu: linux-libre@4.4: Update to 4.4.54.

* gnu/packages/linux.scm (linux-libre-4.4): Update to 4.4.54.

gnu: linux-libre@4.9: Update to 4.9.15.

* gnu/packages/linux.scm (linux-libre-4.9): Update to 4.9.15.

gnu: qemu: Fix CVE-2017-{2620,2630}.

* gnu/packages/patches/qemu-CVE-2017-2620.patch,
gnu/packages/patches/qemu-CVE-2017-2630.patch: New files.
* gnu/local.mk (dist_patch_DATA): Add them.
* gnu/packages/qemu.scm (qemu)[source]: Use them.

gnu: virglrenderer: Fix CVE-2017-6386.

* gnu/packages/patches/virglrenderer-CVE-2017-6386.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/spice.scm (virglrenderer)[source]: Use it.

doc: Reorganize categories.

* doc/guix.texi: Move "guix build" to the "Software Development"
category; add "guix pack".

doc: Mention 'guix pack' reproducibility.

* doc/guix.texi (Invoking guix pack): Mention reproducibility.

pack: Allow for "-S /opt/foo=".

Reported by Andy Wingo.

* guix/scripts/pack.scm (%options): Use 'string-split' instead of
'string-tokenize'.

pack: Honor symlinks in the Docker back-end.

* guix/docker.scm (symlink-source, topmost-component): New procedures.
(build-docker-image): Add #:symlinks parameter and honor it.  Remove
hard-coded /bin symlink.
* guix/scripts/pack.scm (docker-image): Pass #:symlinks to
'build-docker-image'.

docker: Build images in a reproducible fashion.

* guix/docker.scm (%tar-determinism-options): New variable.
(build-docker-image): Use it on the two 'tar' invocations.

pack: Use a fixed timestamp in Docker images.

* guix/docker.scm (build-docker-image): Add #:creation-time parameter.
Use SRFI-19 'date->string' instead of 'strftime' et al.
* guix/scripts/pack.scm (docker-image)[build]: Pass #:creation-time to
'build-docker-image'.

pack: Add '--format' option and Docker output support.

* guix/docker.scm: Remove dependency on (guix store) and (guix utils).
Use (guix build store-copy).  Load (json) lazily.
(build-docker-image): Remove #:system.  Add #:closure, #:compressor, and
'image' parameters.  Use 'uname' to determine the architecture.  Remove
use of 'call-with-temporary-directory'.  Use 'read-reference-graph' to
compute ITEMS.  Honor #:compressor.
* guix/scripts/pack.scm (docker-image): New procedure.
(%default-options): Add 'format'.
(%formats): New variable.
(%options, show-help): Add '--format'.
(guix-pack): Honor '--format'.
* guix/scripts/archive.scm: Remove '--format' option.  This reverts
commits 1545a012cb7cd78e25ed99ecee26df457be590e9,
01445711db6771cea6122859c3f717f130359f55, and
03476a23ff2d4175b7d3c808726178f764359bec.
* doc/guix.texi (Invoking guix pack): Document '--format'.
(Invoking guix archive): Remove documentation of '--format'.