Use clang-format

[dinosaure]

On top of #632, this PR introduce a new GitHub action which verifies that we respect a certain way to write our code. I also applied clang-format on the full codebase which generates a huge diff. I really tried to limit the diff and tweak a bit clang-format. We have two rules: format which calls clang-format -i and format-check which is used by our CI. I also completed the clean rules into the bindings/ directory to delete noexecstack.{c,h,s}.

[hannesm]

I'm not against a formatter, but suggest (a) to add it to .git-blame-ignore-revs, and (b) run it in CI as something that pushes to a PR.

I appreciate the work and the CI job, but I find it much nicer to not bother a contributor to act on some formatting issues. I understand that e.g. dnsvizor/mollymawk have such a CI job which unfortunately at the moment only works for branches of the original repository (not on forks). Maybe this is already the case here?

[dinosaure]

I’ve added the .git-blame-ignore-revs file. As for CI, the first thing is that I haven’t found a satisfactory CI solution that allows me to create a commit applying clang-format, and I’m not keen on using a GitHub Action that isn’t really well maintained.

So I’ve created a new PR that adds docs/contributing.md (see #634), which explains how to apply clang-format and that contributors should add the relevant commit to the .git-blame-ignore-revs file.

I tried to keep the diff as minimal as possible, but not only were quite a few files imported, and the question of style is often very subjective. So I tried to achieve a configuration that was roughly consistent with what I could see in the code.

[hannesm]

cool. the ci check action is already a great thing so we don't end up with unformatted code.

If you're happy with this, please feel free to merge.