Formatted C files

[Richard-Degenne]

This PR is a continuation of the work started in PRs #400 and #409 about issue #393.

I added a .clang-format file enforcing Google-style formatting for C files. I also applied this style to Lwt's C codebase.

Overall, I'm happy with the way the files were indented, even if I find the 80-column limit too strict sometimes (example).

clang-format has quite a lot of options and if you have remarks on what the files look like, please go ahead, I should be able to find the right configuration. :)

[aantron]

Thanks for looking into this!

I haven't reviewed it in any detail yet, but from the CI, it looks like clang-format may have been a little lossy :(

[Richard-Degenne]

I ran the tests on my machine and had no errors. I'll look into it.

[Richard-Degenne]

Nailed it. I think I messed with lwt_unix_stubs.c when browsing it. 🤦‍♂️

[aantron]

😱 <- that should be a reaction option :)

[aantron]

It looks pretty good.

clang-format has quite a lot of options and if you have remarks on what the files look like, please go ahead, I should be able to find the right configuration. :)

Two things jump out:

• I think switching to 4-space indentation would be nice, as this is (or was?) a typical standard for C.
• It would be good to leave the curly braces on function headers (only) alone as they are now, i.e. on new lines.

[aantron]

Thanks for adjusting the rules. The C files look a lot better than their state before this PR, IMO.

I believe two things remain:

• Apply the formatting to our .h files:

  ./src/unix/lwt_unix.h
  ./src/unix/lwt_unix_unix.h
  ./src/unix/lwt_unix_windows.h
  

• Squash this history down a bit. The main goal is to avoid doing two large whitespace changes back-to-back to the same files, since we really mean for it to be one. The original history (one commit to introduce .clang-format and one to apply the changes) is good, or any other history that achieves the goal. I can do this boring stuff, let me know if you'd like me to.

[aantron]

Argh, this build failure suggests that either caml/unixsupport.h or lwt_config.h has to manually be moved above caml/socketaddr.h. This is an upstream issue due to one of the headers not including the other one internally, but we have to work around it :/

[Richard-Degenne]

A trick is to have separate "paragraphs", clang-format will order includes by-paragraph. I've amended the commit. :)

[aantron]

Thanks, I'm learning :)

[aantron]

Much appreciated. I find these files much easier to read now, hopefully others will too.