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.

gnu: Add python-libcst-minimal.

* gnu/packages/python-xyz.scm (python-libcst-minimal): New variable.
(python-libcst): Add a tests? argument to the check phase override and strip
trailing #t.

gnu: python-virtualenv: Update to 20.3.1.

* gnu/packages/python-xyz.scm (python-virtualenv): Update to 20.3.1.
[propagated-inputs]: Remove setuptools and python-importlib-metadata.

gnu: python-flake8-pyi: Update to 20.10.0.

* gnu/packages/python-xyz.scm (python-flake8-pyi): Update to 20.10.0.

gnu: python-hypothesis: Update to 6.0.2

* gnu/packages/check.scm (python-hypothesis): Update to 6.0.2.
(python-hypothesis-5.23): Delete variable.

gnu: python-backpack: Fix build.

* gnu/packages/python-xyz.scm (python-backpack)[native-inputs]: Add python-toml.

gnu: python-simplejson: Update to 3.17.2, fixing build.

* gnu/packages/python-xyz.scm (python-simplejson): Update to 3.17.2.
[native-inputs]: Add python-toml.

gnu: python-babel: Fix build.

* gnu/packages/python-xyz.scm (python-babel)[source]: Re-indent.
[native-inputs]: Add tzdata-for-tests.

gnu: python-3.9: Add a search path specification for PYTHONTZPATH.

Python 3.9 implemented PEP 615 (<)https://www.python.org/dev/peps/pep-0615/>),
which relies on either a compiled time default value or the PYTHONTZPATH
environment variable to find the system tzdata database.

* gnu/packages/python.scm (python-3.9)[native-search-paths]: Add a new search
path specification for PYTHONTZPATH.