Merge of opam-overlays and mirage-opam-overlays

[Virgile Robles <virgile@xxxxxxxxxxx>]

Dear all,

Today our build infrastructure based on opam-monorepo is relying on all unikernel dependencies building with dune. To that end, we have two opam overlay repositories containing ports of packages that do not use dune upstream:

• opam-overlays: historically decoupled from Mirage, containing almost all ports guaranteed to build with dune but not necessarily cross-compilable
• mirage-opam-overlays: for ports that need further or different adaptations to be cross-compilable, since we need it for Mirage.

The second one actually only contains the zarith package, for which we have two different ports.

Following some discussions we had some time ago observing there is some seemingly unnecessary complexity in having two separate repositories for one single package, and that opam-monorepo is (to my knowledge) only used by Mirage, I have merged mirage-opam-overlays into opam-overlays and propose that going forward only opam-overlays be used (and requires that all ports are cross-compilable).

mirage-opam-overlays is now empty and redirecting to opam-overlays, so no unikernels should be affected, but I'm ready to revert if this change broke someone's workflow (Mirage-related or not), so please let me know if this is the case or if you have a use for the non-mirage zarith port!

After some time in the absence of issues I'll submit a PR to mirage/mirage to produce Makefiles without mirage-opam-overlays.

Have a great day,

Virgile