Add base-bytes for OCaml 5.0 support (bytes is not a dune builtin anymore since OCaml 5.0)

[kit-ty-kate]

In opam-repository, base-bytes depends on ocamlfind which installs a dummy META file for the bytes package.
With OCaml 5.0 dune does not have any builtin packages anymore and thus relies on the META files given by ocamlfind for bytes.

However in mirage context ocamlfind is not installed, thus we need a dummy package providing bytes otherwise we are unable to compile any mirage projects in OCaml 5.0

[Leonidas-from-XIV]

Ah yes, I can see how this makes sense. I'm slightly worried about packages implicitly depending on ocamlfind via base-bytes but frankly these packages (if they exist) have wrong metadata anyway and should be fixed elsewhere.

Can you make a tarball with the release? That way it'll be more universal and faster to install since that way the git client is not required and the tarball can be checksummed easily.

[kit-ty-kate]

Done

[Leonidas-from-XIV]

Thanks, that seems good!

[avsm]

This appears to break any compiler < 5.0.0, e.g. realworldocaml/book#3656 with a duplicate rule for the bytes META file.

Error: Multiple rules generated for _build/install/default/lib/bytes/META:
2924	
- duniverse/lib-findlib/site-lib-src/dune:6
2925	
- _build/default/duniverse/bytes/META.bytes:1
2926	
-> required by alias duniverse/lib-findlib/.findlib-files
2927	
-> required by alias duniverse/lib-findlib/.ocamlfind-files
2928	
-> required by
2929	
   _build/default/book/files-modules-and-programs/.mdx/README.md.corrected
2930	
-> required by alias book/files-modules-and-programs/runtest in
2931	
   book/files-modules-and-programs/dune:1
2932	

[Leonidas-from-XIV]

@avsm Thanks for the report! I've submitted a PR to fix up opam-overlays: #179

[avsm]

It concerns me that all compilers < 5.0 have been broken since November. Is there a CI test in place that would test your fix?