git: 'commit-difference' really excludes the ancestors of #:excluded.

* guix/git.scm (commit-difference): Initialize VISITED to the closure of
OLD and EXCLUDED, as written in the docstring.
* tests/git.scm ("commit-difference, excluded commits"): Adjust
accordingly.

maint: 'make authenticate' starts from v1.0.0.

* Makefile.am (commit_v1_0_1): Remove.
(commit_v1_0_0): New variable.
(authenticate): Use it.

gnu: znc: Update to 1.8.1.

* gnu/packages/messaging.scm (znc): Update to 1.8.1.

gnu: v4l2loopback-linux-module: Really disable tests.

Commit fdcd193744dbb92d3478c8e4e6c4f4336a872831 was a botched by-hand
‘merge’ that caused the default check phase to run, and fail.

* gnu/packages/linux.scm (v4l2loopback-linux-module)[arguments]:
Set #:tests? to #f.

gnu: Add linux-libre-arm-generic-5.7.

* gnu/packages/linux (linux-libre-arm-generic): New variable.

gnu: Add linux-libre-arm64-generic-5.7.

* gnu/packages/linux (linux-libre-arm64-generic): New variable.

gnu: Add linux-libre 5.7.1.

* gnu/packages/linux (deblob-scripts-5.7): New variable.
  (linux-libre-5.7-version): New variable.
  (linux-libre-5.7-pristine-source): New variable.
  (linux-libre-5.7-source): New variable.
  (linux-libre-headers-5.7): New variable.

gnu: opensmtpd: Patch bug in 'smtpctl encrypt'.

* gnu/packages/mail.scm (opensmtpd)[phases]{fix-smtpctl-encrypt-bug}: New
phase.

gnu: Blender: Update to 2.83.0.

* gnu/packages/graphics.scm (blender): Update to 2.83.0.

gnu: font-liberation: Update to 2.1.1.

* gnu/packages/fonts.scm (font-liberation): Update to 2.1.1.

gnu: Add python-mechanize.

* gnu/packages/python-xyz.scm (python2-mechanize): Rename to ...
(python-mechanize): ... this.  Update to 0.4.5.
[arguments]: Remove.
[propagated-inputs]: Add PYTHON-HTML5LIB.
[home-page]: Update to current.
[license]: Set to LICENSE:BSD-3.
(python2-mechanize): Define in terms of PACKAGE-WITH-PYTHON2.

gnu: python-regex: Update to 2020.6.8.

* gnu/packages/python-xyz.scm (python-regex): Update to 2020.6.8.
[arguments]: New field.

gnu: python-netifaces: Update to 0.10.9.

* gnu/packages/python-xyz.scm (python-netifaces): Update to 0.10.9.

gnu: python-cssselect: Update to 1.1.0.

* gnu/packages/python-web.scm (python-cssselect): Update to 1.1.0.
[source]: Change to GIT-FETCH.
[arguments]: Remove #:tests?.  Add #:phases.
[native-inputs]: Add PYTHON-LXML and PYTHON-PYTEST.
[home-page]: Update to current.

gnu: python-odfpy: Update to 1.4.1.

* gnu/packages/python-xyz.scm (python-odfpy): Update to 1.4.1.
[arguments]: Remove #:modules.  Rewrite test phase to use pytest.
[native-inputs]: Add PYTHON-PYTEST.
[propagated-inputs]: Add PYTHON-DEFUSEDXML.

gnu: openssh: Remove exception to build without xauth for the Hurd.

* gnu/packages/ssh.scm (openssh)[inputs]: Unconditionally include xauth;
for the Hurd: use openssh-sans-x for now.

gnu: guix: Update to ab9e30039d.

* gnu/packages/package-management.scm (guix): Update to 1.1.0-1.ab9e30039d.

syscalls: set-thread-name, thread-name: Fix thinko.

* guix/build/syscalls.scm (set-thread-name, thread-name): Oops, fix thinko.

gnu: guix: Update to 68d8c09465.

* gnu/packages/package-management.scm (guix): Update to 1.1.0-1.68d8c09465.

gnu: services: Add %hurd-startup-service.

This decouples startup of the Hurd from the "hurd" package, moving the RC
script into SYSTEM.

* gnu/packages/hurd.scm (hurd)[inputs]: Remove hurd-rc-script.
[arguments]: Do not substitute it.  Update "runsystem.sh" to parse kernel
arguments and exec into --system=SYSTEM/rc.
(hurd-rc-script): Move to...
* gnu/services.scm (%hurd-rc-file): ...this new variable.
(hurd-rc-entry): New procedure.
(%hurd-startup-service): Use it in new variable.
* gnu/system.scm (hurd-default-essential-services): Use it.