[#266] Configure bindgen to bind dirfd C macro on macOS

[orecham]

Notes for Reviewer

Forwards calls to dirent to C macro defined on macOS platform.
Only required on macOS as dirent is declared as a function on other platforms.

Pre-Review Checklist for the PR Author

1. Add sensible notes for the reviewer
2. PR title is short, expressive and meaningful
3. Relevant issues are linked in the References section
4. Every source code file has a copyright header with SPDX-License-Identifier: Apache-2.0 OR MIT
5. Branch follows the naming format (iox2-123-introduce-posix-ipc-example)
6. Commits messages are according to this guideline
   • Commit messages have the issue ID ([#123] Add posix ipc example)
   • Commit author matches Eclipse Contributor Agreement (and ECA is signed)
7. Assign PR to reviewer
8. All checks have passed (except task-list-completed)

Checklist for the PR Reviewer

• Commits are properly organized and messages are according to the guideline
• Unit tests have been written for new behavior
• Public API is documented
• PR title describes the changes

Post-review Checklist for the PR Author

1. All open points are addressed and tracked via issues

References

Closes #266

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.75%. Comparing base (a83c2ec) to head (18d6c8b).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #267      +/-   ##
==========================================
- Coverage   79.79%   79.75%   -0.05%     
==========================================
  Files         191      191              
  Lines       21468    21468              
==========================================
- Hits        17130    17121       -9     
- Misses       4338     4347       +9     

see 1 file with indirect coverage changes