* guix/channels.scm (<channel-metadata>)[news-file]: New field.
(read-channel-metadata): Set the 'news-file' field.
(read-channel-metadata-from-source): Likewise.
(<channel-news>, <channel-news-entry>): New record types.
(sexp->channel-news-entry, read-channel-news)
(channel-news-for-commit): New procedures.
* guix/tests/git.scm (populate-git-repository): For 'add', allow
CONTENTS to be a procedure.
* tests/channels.scm ("channel-news, no news")
("channel-news, one entry"): New tests.
* doc/guix.texi (Channels): Document it.

* guix/git.scm (commit-closure, commit-difference): New procedures.
* guix/tests/git.scm, tests/git.scm: New files.
* Makefile.am (dist_noinst_DATA): Add guix/tests/git.scm.
(SCM_TESTS): Add tests/git.scm.

* guix/git.scm (reference-available?): New procedure.
(update-cached-checkout): Avoid call to 'remote-fetch' when REPOSITORY
already contains REF.

* guix/scripts/pull.scm (display-channel, channel=?)
(display-channel-news, display-news): New procedures.
(process-query): Call 'display-news' instead of 'display-profile-news'.

* gnu/packages/xdisorg.scm (wl-clipboard): Update to 2.0.0_beta2.

* gnu/packages/gdb.scm (gdb-8.3): Update to 8.3.1.

* gnu/packages/datamash.scm (datamash): Update to 1.5.

* gnu/packages/emacs-xyz.scm (emacs-suggest): Enable tests.

* gnu/packages/emacs-xyz.scm (emacs-helpful): Enable tests.

* gnu/packages/emacs-xyz.scm (emacs-ht): Enable tests.

* gnu/packages/emacs-xyz.scm (emacs-tco-el): Enable tests.

* gnu/packages/emacs-xyz.scm (emacs-loop): Enable tests.

* gnu/packages/emacs-xyz.scm (emacs-elisp-refs): Enable tests.

* gnu/packages/emacs-xyz.scm (emacs-realgud): Update to 1.5.1.

* gnu/packages/emacs-xyz.scm (emacs-company-lsp): Enable tests.

* gnu/packages/javascript.scm (js-datatables): Update to 1.10.19.

* gnu/packages/parallel.scm (parallel): Update to 20190922.

* gnu/packages/engineering.scm (freecad): New variable.

* gnu/packages/engineering.scm (libmedfile): New variable.

* gnu/packages/engineering.scm (libarea): New variable.

* gnu/packages/engineering.scm (libspnav): New variable.

* gnu/packages/qt.scm (python-pyside-2-tools): New variable.

 * gnu/packages/qt.scm (python-pyside-2): New variable.

* gnu/packages/llvm.scm (libcxx-6): New variable.

* gnu/packages/qt.scm (python-shiboken-2): New variable.

* gnu/packages/graphics.scm (coin3D): New variable.

* gnu/packages/emacs-xyz.scm (emacs-company-lua): Update to 0.1-2.29f6819.
[arguments]: Include extra directory.

* gnu/packages/emacs-xyz.scm (emacs-crux): Update to 0.3.0-2.308f17d.

* gnu/packages/emacs-xyz.scm (emacs-lispy): Update included files.

* gnu/packages/diffoscope (diffoscope)[native-inputs]: Only add ghc on
  x86_64-linux and i686-linux.
  Only add openjdk and enjarify on x86_64-linux.

* gnu/packages/mail.scm (mutt): Update to 1.12.2.

* gnu/packages/emacs-xyz.scm (emacs-attrap): Update to 1.0-2.18cd1f7.

* gnu/packages/emacs-xyz.scm (emacs-github-review): Enable tests.

* gnu/packages/emacs-xyz.scm (emacs-elfeed): Update to 3.2.0.

* gnu/packages/gnome.scm (libgnomekbd)[source]: Hard-code NAME.

* gnu/packages/gnome.scm (libgnomekbd): Update to 3.26.1.

* gnu/packages/maths.scm (wxmaxima): Update to 19.09.0.

As defaulting by stderr, along with the shepherd service not directing the
output to a log file makes seeing the output difficult, compared to logging to
syslog.

* gnu/services/virtualization.scm (libvirt-configuration)[log-outputs]: Change
default from "3:stderr" to "3:syslog:libvirtd".

Otherwise the .go files appear within share, and Guile doesn't find them. With
this patch they appear in lib within the output. One thing this means is that
stack traces include the filenames.

* gnu/packages/guile-xyz.scm (guile-email)[arguments]: Add 'patch-module-dir
phase.

* guix/scripts/package.scm (process-query) <'show>: Remove superseded
packages.
* tests/guix-package-aliases.sh: Add test.