CI: clang-format occasionally miss-fires
In some care cases, the clang-format lint stage will fail ... Even though the MR has zero code code-change commits.
Haven't looked into it - some random ideas:
- is it because the MR was originally targeting master, vs which there are code changes
- the correct magic (CI) variable is not set, correctly(?)
For example:
- MR !138 (closed)
- Failing pipeline https://gitlab.freedesktop.org/xexaxo/waffle/-/jobs/49670257