gnu: Add emacs-bongo.

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

gnu: snakemake: Update to 4.4.0.

* gnu/packages/python.scm (snakemake): Update to 4.4.0.

gnu: elixir: Update to 1.5.3.

* gnu/packages/elixir.scm (elixir): Update to 1.5.3.

gnu: services: Add darkstat service.

* gnu/services/monitoring.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
* doc/guix.texi (Monitoring Services): Document it.

gnu: Add darkstat.

* gnu/packages/monitoring.scm (darkstat): New variable.

import: crate: Gracefully deal with missing license info.

Reported by Fis Trivial <ybbs.daans@hotmail.com>.
Fixes <https://bugs.gnu.org/28987>.

* guix/import/crate.scm (crate-fetch): Check whether the "license" info
is present.

services: guix: Add 'log-compression' option.

* gnu/services/base.scm (<guix-configuration>)[log-compression]: New
field.
(guix-shepherd-service): Use 'match-record' instead of 'match'.  Honor
'log-compression'.
* doc/guix.texi (Base Services): Document 'log-compression'.

gnu: Add html-xml-utils.

* gnu/packages/xml.scm (html-xml-utils): New variable.

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

gnu: Add rtags.

* gnu/packages/code.scm (rtags): New public variable.

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

gnu: guix: Update snapshot to c04ffad.

* gnu/packages/package-management.scm (guix): Update to c04ffad.

gnu: youtube-dl: Update to 2018.01.07.

* gnu/packages/video.scm (youtube-dl): Update to 2018.01.07.

gnu: nano: Update to 2.9.2.

* gnu/packages/nano.scm (nano): Update to 2.9.2.

gnu: borg: Unbundle libb2.

* gnu/packages/backup.scm (borg)[source]: Remove bundled libb2 in snippet.
[inputs]: Add libb2.
[arguments]: Use it.

gnu: Add libb2.

* gnu/packages/crypto.scm (libb2): New public variable.

gnu: Add missing copyright line.

* gnu/packages/check.scm: Add copyright line for 18a4d6d.

gnu: Add python-pyhamcrest.

* gnu/packages/check.scm (python-pyhamcrest, python2-pyhamcrest): New
variables.

Signed-off-by: Kei Kebreau <kkebreau@posteo.net>

publish: Publish build logs.

* guix/scripts/publish.scm (render-log-file): New procedure.
(make-request-handler): Add "log" case.
* tests/publish.scm ("/log/NAME")
("/log/NAME not found"): New tests.
* doc/guix.texi (Invoking guix publish): Document /log URLs.

publish: Use 'x-raw-file' internal response header.

This adjusts the workaround for <http://bugs.gnu.org/21093> so that it's
not limited to a single content-type.

* guix/scripts/publish.scm (render-nar/cached): Add the 'x-raw-file'
header on the response.
(render-content-addressed-file): Likewise.
(with-content-length): Remove the 'x-raw-file' header.
(http-write): Instead of dispatching on 'application/octet-stream',
check whether 'x-raw-file' is set to determine whether to spawn a
thread.

doc: Mark zlib as mandatory, libbz2 as optional.

* doc/guix.texi (Requirements): Move zlib to mandatory and libbz2 to
optional.
* README: Ditto.

daemon: Make libbz2 an optional dependency.

* config-daemon.ac: Don't bail out when libbz2 is missing.  Define
'HAVE_LIBBZ2' Automake conditional.
* nix/libstore/build.cc: Wrap relevant bits in '#if HAVE_BZLIB_H'.
* nix/libstore/globals.cc (Settings::Settings): 'logCompression'
defaults to COMPRESSION_GZIP when HAVE_BZLIB_H is false.
* nix/libstore/globals.hh (CompressionType): Make 'COMPRESSION_BZIP2'
conditional on HAVE_BZLIB_H.
* nix/local.mk (guix_register_LDADD, guix_daemon_LDADD): Add -lbz2 only
when HAVE_LIBBZ2.
* nix/nix-daemon/guix-daemon.cc (parse_opt): Ignore "bzip2" when not
HAVE_BZLIB_H.