gnu: python-black: Remove blackd.

* gnu/packages/python-xyz.scm (python-black) [arguments]: Add new phase
to prevent installation of blackd.

gnu: python-websockets: Fix Python package name.

* gnu/packages/python-web.scm (python-websockets) [arguments]: Add new
phase to fix package name.

gnu: python-slugify: Add missing input.

* gnu/packages/python-web.scm (python-slugify) [propagated-inputs]: Add
python-text-unidecode.

gnu: python-pyfakefs: Disable unreliable test

* gnu/packages/check.scm (python-pyfakefs) [arguments]: Add new phase to
skip single test.

gnu: python-pytest-pep8: Fix package.

* gnu/packages/check.scm (python-pytest-pep8)[arguments]: Remove
dependency on pytest-cache and add proper 'check phase.

gnu: python-fixtures-bootstrap: Do not sanity check.

* gnu/packages/check.scm (python-fixtures-bootstrap)
[phases]{sanity-check}: Delete.

gnu: python-pytest-xdist: Add missing input, relax pytest requirement.

* gnu/packages/check.scm: (python-pytest-xdist)
[arguments]: Relax pytest version requirements.
[propagated-inputs]: Add python-pytest-forked.

build/python: Add a sanity check phase.

Add a new phase validating the usability of installed Python packages.

* gnu/packages/aux-files/python/sanity-check.py: New file.
* Makefile.am (AUX_FILES): Register it.
* guix/build-system/python.scm (sanity-check.py): New variable.
(lower): Add the script as an implicit input.
* guix/build/python-build-system.scm: Remove trailing #t.
(sanity-check): New phase.
(%standard-phases): Use it.
* tests/builders.scm: (make-python-dummy)
(dummy-ok, dummy-dummy-nosetuptools, dummy-fail-requirements)
(dummy-fail-import, dummy-fail-console-script): New variables.
("python-build-system: dummy-ok")
("python-build-system: dummy-dummy-nosetuptools")
("python-build-system: dummy-fail-requirements")
("python-build-system: dummy-fail-import")
("python-build-system: dummy-fail-console-script"): Add tests.

build/python: Adjust wrap phase to use the new GUIX_PYTHONPATH.

* guix/build/python-build-system.scm (wrap): Adjust to use the new
GUIX_PYTHONPATH.  Remove trailing #t.

build/python: Add the installation bin directory to PATH.

This also to reduce the need for boilerplate code found in check phase
overrides.

* guix/build/python-build-system.scm (add-install-to-path): New phase.
(%standard-phases): Order it before the check phase.

build/python: Always add the install prefix to the Guix PYTHONPATH.

This is to remove the need for common boilerplate code in check phase
overrides.

* guix/build/python-build-system.scm
(add-installed-pythonpath): Streamline.  This phase depends on the presence of
a "python" input; thus GUIX_PYTHONPATH is guaranteed to be defined.  Update doc.
(add-install-to-pythonpath): New phase.
(%standard-phases): Order it before the check phase.

build/python: Replace PYTHONPATH by GUIX_PYTHONPATH.

* guix/build/python-build-system.scm (add-installed-pythonpath): Replace
"PYTHONPATH" by "GUIX_PYTHONPATH".

gnu: python: Replace PYTHONPATH by GUIX_PYTHONPATH.

Using PYTHONPATH as a mean to discover the Python packages had the following
issues:

        1. It is not versioned, so different versions of Python would clash if
        installed in a shared profile.

        2. It would interfere with the host Python site on foreign
        distributions, sometimes preventing a a user to login their GDM
        session (!).

        3. It would take precedence over user installed Python packages
        installed through pip.

        4. It would leak into Python virtualenvs, which are supposed to create
        isolated Python environments.

This changes fixes the above issues by making use of a sitecustomize.py
module.  The newly introduced GUIX_PYTHONPATH environment variable is read
from the environment, filtered for the current Python version of the
interpreter, and spliced in 'sys.path' just before Python's own site location,
which provides the expected behavior.

* gnu/packages/aux-files/python/sitecustomize.py: New file.
* Makefile.am: Register it.
* gnu/packages/python.scm (customize-site)
(guix-pythonpath-search-path): New procedures.
(python-2.7)[phases]{install-sitecustomize.py}: New phase.
[native-inputs]{sitecustomize.py}: New input.
[native-search-paths]: Replace PYTHONPATH with GUIX_PYTHONPATH.
(python-3.9)[native-search-paths]: Likewise.
[phases]{install-sitecustomize}: Override with correct version.
[native-search-paths]: Replace PYTHONPATH with GUIX_PYTHONPATH.
* gnu/packages/commencement.scm (python-boot0):
[phases]{install-sitecustomize}: Likewise.
[native-inputs]{sitecustomize.py}: New input.
[native-search-paths]: Replace PYTHONPATH with GUIX_PYTHONPATH.
* guix/build/python-build-system.scm (site-packages): Do not add a trailing
'/'.

squash! gnu: python: Replace PYTHONPATH by GUIX_PYTHONPATH.

gnu: pixman: Update to 0.40.0.

* gnu/packages/xdisorg.scm (pixman) [version]: Update to 0.40.0.
[license]: Change from X11 to expat.

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

gnu: pixman: Enable some features.

* gnu/packages/xdisorg.scm (pixman) [arguments] Pass --enable-timers and
--enable-gnuplot to #:configure-flags.

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

gnu: openjpeg: Enable tests.

* gnu/packages/image.scm (openjpeg)[arguments]: Enable the test suite.
Pass -DBUILD_UNIT_TESTS, -DBUILD_TESTING, and -DOPJ_DATA_ROOT
to #:configure-flags. Add a new 'disable-failing-tests' phase.
[native-inputs]: Add openjpeg-data.

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

gnu: fontconfig: Update to 2.13.93.

* gnu/packages/patches/fontconfig-hurd-path-max.patch: Delete file.
* gnu/local.mk (dist_patch_DATA): Un-register file.
* gnu/packages/fontutils.scm (fontconfig)[source]
{uri}: Use the .tar.xz archive.
{patches}: Remove field.  The patch was merged upstream.
[native-inputs]: Add python-minimal.
[phases]{skip-problematic-tests}: Add phase.
[configure-flags]: Do not set PYTHON to false.
* gnu/packages/fontutils.scm (fontconfig-with-documentation)
[native-inputs]: Add docbook-utils.

gnu: fontconfig-with-documentation: New variable.

In what will become fontconfig 2.14, the complete documentation of fontconfig
requires multiple dependencies that would be problematic to add to this core
package; instead, keep the 'fontconfig' variable package lean and create a new
'fontconfig-with-documentation' package that will be known as "fontconfig" to
the users.

* gnu/packages/fontutils.scm (fontconfig): Hide package.
[outputs]: Remove doc output.
[configure-flags]: Add "--disable-docs" argument.
[phases]{remove-pdf-files}: Remove phase.
{move-man-sections}: Move to...
(fontconfig-with-documentation): ... this new variable with a doc output.

gnu: Replace all uses of texlive-union by texlive-updmap.cfg.

* doc/build.scm (pdf-manual) Replace texlive-union by texlive-updmap.cfg.
* gnu/packages/algebra.scm (pari-gp): Likewise.
* gnu/packages/bioinformatics.scm (discrover, velvet): Likewise.
* gnu/packages/chez.scm (chez-scheme, chez-web, chez-sockets): Likewise.
* gnu/packages/docbook.scm (dblatex): Likewise.
* gnu/packages/emacs-xyz.scm (emacs-auctex): Likewise.
* gnu/packages/engineering.scm (fastcap): Likewise.
* gnu/packages/guile-xyz.scm (emacsy, guile-cv): Likewise.
* gnu/packages/lisp.scm (sbcl): Likewise.
* gnu/packages/maths.scm (octave, hypre): Likewise.
* gnu/packages/music.scm (lilypond): Likewise.
* gnu/packages/plotutils.scm (asymptote): Likewise.
* gnu/packages/python-xyz.scm (python-numpy-documentation)
(python-matplotlib-documentation, python-ipython-documentation)
(python-pypandoc): Likewise.
* gnu/packages/radio.scm (gnuradio, libosmo-dsp): Likewise.
* gnu/packages/scheme.scm (mit-scheme): Likewise.
* gnu/packages/statistics.scm (r-with-tests): Likewise.
* gnu/packages/tex.scm (simple-texlive-package)
(texlive-xmltex, texlive-tiny, texlive-jadetex, teximpatient, lyx): Likewise.

gnu: texlive-amsfonts: Adjust to build with texlive-updmap.cfg.

* gnu/packages/tex.scm (texlive-amsfonts)[phases]
{build-fonts}: Do not set SOURCE_DATE_EPOCH, already done by the build
system.  Let resources be auto-discovered by TeX Live machinery by simply
setting GUIX_TEXMF.  Remove references to the texlive-union input.  Remove
trailing #t.
{install-generated-fonts}: Remove trailing #t.
[native-inputs]: Replace texlive-union by texlive-updmap.cfg.  Remove the
texlive-cm and texlive-metafont arguments of texlive-updmap.cfg.