OCaml 5 has a compaction phase in the GC again, and in some ways even better than OCaml 4's! Now has really nice transparent superpage coalescing as well, for the size-segment pools for larger allocations present in OCaml 5.0+. This feature will be present in OCaml 5.2 onwards. https://github.com/ocaml/ocaml/pull/12193

@avsm fantastically poor choice of pull request title