[PATCH v2 0/5] Address some issues with sphinx detection

[Mauro Carvalho Chehab]

Checking if Sphinx is available and read to run is tricky, and may involve
installing several packages for the document build to happen.

There are two options to install Sphinx:

	- via distro-provided packages;
	- via pip, using virtualenv/venv.

Some recent discussions showed a couple of misleading instructions.

This series improves the Sphinx detection by:

- Fixing the logich with checks if a past venv is working and recommend
  just enabling it instead of installing a new venv;
- Detect if sphinx-build stopped working on a venv. This may happen during
  distribution updates;
- Move the PDF minimal version to be later, in order for it to be printed only
  after finishing the Sphinx version check;

Additionally, as now the Sphinx provided on almost all modern distros are
above the minimal required version, place instructions about how to install
Sphinx from the distro-provided packages after placing the instructions for
installing it via venv.

This will hopefully help to have more developers checking documentation
builds with

	make htmldocs

---

v2:
- Fix some issues at the logic that was recommending installing via
  distro-package manager;
- Add a notice about Sphinx 3.0+ false-positive warnings due to a
  Sphinx bug. People using a version different than the recommended
  one should know about that.

Mauro Carvalho Chehab (5):
  scripts: sphinx-pre-install: fix venv version check logic
  scripts: sphinx-pre-install: report broken venv
  scripts: sphinx-pre-install: check for PDF min version later on
  scripts: sphinx-pre-install: provide both venv and package installs
  scripts: sphinx-pre-install: place a warning for Sphinx >= 3.0

 scripts/sphinx-pre-install | 90 +++++++++++++++++++++++++++++---------
 1 file changed, 69 insertions(+), 21 deletions(-)

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2.36.1