* guix/scripts/pull.scm (display-news-entry)
(display-channel-specific-news): New procedures.
(display-channel-news): Call it.
(display-new/upgraded-packages): Adjust hint message.
* doc/guix.texi (Invoking guix pull): Mention it.

* guix/ui.scm (%default-message-language): New variable.
(current-message-language): New procedure.

Suggested by Ricardo Wurmus <rekado@elephly.net>.

* guix/channels.scm (<channel-news-entry>)[tag]: New field.
(sexp->channel-news-entry): Accept either 'commit' or 'tag' in 'entry'
forms.
(resolve-channel-news-entry-tag): New procedure.
(channel-news-for-commit): Move 'with-repository' form one level
higher.  Call 'resolve-channel-news-entry-tag' on all the news entries.
* guix/tests/git.scm (populate-git-repository): Add clause for 'tag'.
* tests/channels.scm ("channel-news, one entry"): Create a tag and add
an entry with a tag.  Check that the tag is resolved and also visible in
the <channel-news-entry> record.
* doc/guix.texi (Channels): Mention tags in news entries.

* 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.