Make signal handling work on OCaml 5 and with Eio#993

Merged

raphael-proust merged 4 commits intoocsigen:masterfrom talex5:forward-signals

Jul 17, 2023

+64-13

Commits on Jun 21, 2023

On OCaml 5, use SA_ONSTACK to avoid corrupting memory
talex5
committed

Commits on Jun 22, 2023

Lwt_engine: allow external signal handlers
talex5
committed

Commits on Jul 12, 2023

Fix signal masking race in worker_loop
talex5
committed

Commits on Jul 17, 2023

Mention addition in CHANGES
raphael-proust
committed