gnu: mercurial: Update to 5.6.1.

This fixes the build on Python 3.9.

* gnu/packages/version-control.scm (mercurial): Update to 5.6.1.  Delete
trailing #t.
[phases]{check}: Remove the "test-transaction-rollback-on-sigpipe.t" test
file and add a comment.

gnu: bison: Update to 3.7.5.

* gnu/packages/bison.scm (bison): Update to 3.7.5.

gnu: binutils: Update to 2.36.

* gnu/packages/base.scm (binutils): Update to 2.36.

gnu: %boot-tcc-inputs: Use gash-utils.

* gnu/packages/commencement.scm (%boot-tcc-inputs): Remove
diffutils-mesboot. Add gash-utils-boot.
(diffutils-mesboot): Remove variable.

gnu: guile: Disable parallel builds.

This works around <https://bugs.gnu.org/20272>, as discussed in
<https://lists.gnu.org/archive/html/guix-devel/2021-01/msg00273.html>.

* gnu/packages/guile.scm (guile-2.0)[arguments]: Pass #:parallel-build? #f.

gnu: ibus: Remove dependency on GConf.

GConf has been deprecated for a while.  This change removes GConf (and
thus ORBit) from the closure of GNOME.

* gnu/packages/ibus.scm (ibus)[inputs]: Remove GCONF.

gnu: zziplib: Update to 0.13.72.

* gnu/packages/compression.scm (zziplib): Update to 0.13.72.
[build-system]: Use cmake-build-system
[arguments]: Remove field.

Signed-off-by: Leo Famulari <leo@famulari.name>

gnu: libdrm: Update to 2.4.104.

* gnu/packages/xdisorg.scm (libdrm): Update to 2.4.104.

Signed-off-by: Leo Famulari <leo@famulari.name>

gnu: libarchive: Update to 3.5.1.

* gnu/packages/backup.scm (libarchive): Update to 3.5.1.

Signed-off-by: Leo Famulari <leo@famulari.name>

gnu: automake: Update to 1.16.3.

* gnu/packages/autotools.scm (automake): Update to 1.16.3.

packages: 'patch-and-repack' returns a directory when given a directory.

Previously, 'patch-and-repack' would always create a tar.xz archive as a
result, even if the input was a directory (a checkout).  This change
reduces gratuitous CPU and storage overhead.

* guix/packages.scm (patch-and-repack)[tarxz-name]: Remove 'checkout?' case.
[build](repack): New procedure, with "tar" invocation formerly at the
top level.
If SOURCE is a directory, call 'copy-recursively'; otherwise, call
'repack'.
Change NAME to ORIGINAL-FILE-NAME when it matches 'checkout?'.

gnu: python-isort: Update to 5.7.0, fixing build on Python 3.9.

* gnu/packages/python-xyz.scm (python-isort): Update to 5.7.0.
[source]: Delete checked in binary wheels in a snippet.
[arguments]: New field.
[phases]: Replace the build and install phases, implementing the basics of a
PEP 517 build system.
{check}: Override phase.
{install-example-plugins}: New phase.
[native-inputs]: Remove python-mock.  Add git-minimal, python-black,
python-colorama, python-hypothesmith, python-libcst-minimal,
python-poetry-core, python-pylama, python-pypa-build and python-pytest-mock.
[home-page]: Update home page.

gnu: python2-isort: Remove package.

* gnu/packages/python-xyz.scm (python-isort)[properties]: Remove field.
(python2-isort): Delete variable.

gnu: python2-factory-boy: Remove package.

* gnu/packages/python-xyz.scm (python2-factory-boy): Remove variable.

gnu: python2-orator: Remove package.

* gnu/packages/databases.scm (python-orator)[properties]: Delete field.
(python2-orator): Remove variable.

gnu: python2-pylint: Remove package.

* gnu/packages/check.scm (python-pylint)[properties]: Delete field.
* gnu/packages/check.scm (python2-pylint): Remove variable.

gnu: Add python-pylama.

* gnu/packages/python-check.scm (python-pylama): New variable.

gnu: Add python-mypy-minimal.

* gnu/packages/python-check.scm (python-mypy-minimal): New variable.

gnu: python-typing-inspect: Fix build on Python 3.9.

* gnu/packages/patches/python-typing-inspect-fix.patch: Add patch.
* gnu/local.mk (dist_patch_DATA): Register it.
* gnu/packages/python-xyz.scm (python-typing-inspect)[patches]: Apply it.

gnu: python-hypothesmith: Update to 0.1.8.

* gnu/packages/check.scm (python-hypothesmith): Update to 0.1.8.
[propagated-inputs]: Replace python-hypothesmith-5.23 by python-hypothesmith.