[PATCH 0/8] Parallel docs build improvements

[Antonin Godard <antonin.godard@bootlin.com>]

The aim of this series is to take the work of Quentin[1] and with
additional commit that improve the concurrent safety of the docs build,
and some general improvements to the build-docs-container script.

This allows building the docs on all supported distros with this bash
snippet:

```
declare -a distros=( $(./documentation/tools/build-docs-container supported_distros) )

for distro in "${distros[@]}"; do
  ./documentation/tools/build-docs-container $distro "$target" >/tmp/docs-build-"$distro".log 2>&1 &
done

wait
```

Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
---
Antonin Godard (6):
      tools/build-docs-container: build in separate directory for each distro
      tools/build-docs-container: create symlink to latest build output
      Makefile: wrap set_versions.py with flock
      tools/build-docs-container: allow running non-interactively
      tools/build-docs-container: allow passing extra args to $OCI run
      tools/build-docs-container: make it possible to print the distro list

Quentin Schulz (2):
      tools/build-docs-container: guarantee the image to run matches the just-built image
      Makefile: allow to specify build directory

 documentation/.gitignore                 |  1 +
 documentation/Makefile                   | 10 ++--
 documentation/tools/build-docs-container | 90 +++++++++++++++++++++++---------
 3 files changed, 71 insertions(+), 30 deletions(-)
---
base-commit: f9042e1da554017fe46460c1fd2bdf8c74b3fa18
change-id: 20251218-concurrent-safety-e3a1a2394064