bug#51866: OCaml4.07: build fail because Dune version

[zimoun]

Hi,

These OCaml packages fail to build because some issue with Dune
versions, respectively:

--8<---------------cut here---------------start------------->8---
ocaml4.07-charinfo-width
ocaml4.07-core
ocaml4.07-core-kernel
ocaml4.07-ezjsonm
ocaml4.07-lambda-term
ocaml4.07-merlin
ocaml4.07-odoc
ocaml4.07-piqi
ocaml4.07-piqilib
ocaml4.07-ppx-expect
ocaml4.07-ppx-jane
ocaml4.07-sedlex
ocaml4.07-spawn
ocaml4.07-splittable-random
ocaml4.07-sqlite3
ocaml4.07-uri
ocaml4.07-utop
ocaml4.07-zed
--8<---------------cut here---------------end--------------->8---

fails because:

--8<---------------cut here---------------start------------->8---
Error: Version 2.0 of dune is not supported.
Error: Version 2.0 of dune is not supported.
Error: Version 2.0 of dune is not supported.
Error: Version 2.0 of dune is not supported.
Error: Version 2.7 of dune is not supported.
Error: Version 2.0 of dune is not supported.
Error: Version 2.7 of dune is not supported.
Error: Version 2.7 of dune is not supported.
Error: Version 2.7 of dune is not supported.
Error: Version 2.0 of dune is not supported.
Error: Version 2.0 of dune is not supported.
Error: Version 2.7 of dune is not supported.
Error: Version 2.0 of dune is not supported.
Error: Version 2.0 of dune is not supported.
Error: Version 2.7 of dune is not supported.
Error: Version 2.0 of dune is not supported.
Error: Version 2.7 of dune is not supported.
Error: Version 2.0 of dune is not supported.
--8<---------------cut here---------------end--------------->8---


>From my understanding, more or more cases like this will happen.  The
question is: do we try to fix?  Or do we plan to remove ’ocaml4.07-’
packages?


Cheers,
simon