packaging issues of 2.1.5 for FreeBSD

[hannesm]

Dear Madam or Sir,

as an update to #4894 there is still some patching needed to get opam 2.1.5 into FreeBSD. As a quick reminder, we use the opam-full tarball and bootstrap the OCaml compiler distributed with that tarball.

The issue is ocaml/ocaml#9800 (fixed in 4.14.0 - but opam 2.1.5 still ships with 4.13.1 (the bug is fixed in 4.14.0)).

I'm curious whether you'd consider:

• (a) updgrade the OCaml version for the 2.1 branch (depends on your mileage and your general direction in respect to 2.2)
• (b) for the future, embed a patch for bootstrap.sh that allows patches for the OCaml distribution (see https://github.com/freebsd/freebsd-ports/blob/main/devel/ocaml-opam/files/patch-shell_bootstrap-ocaml.sh -- which allows https://github.com/freebsd/freebsd-ports/blob/main/devel/ocaml-opam/files/patch-src__ext_ocaml-patches_0001-Fix-relocation-ocaml-32-bit.patch that makes ocaml-opam 2.1.5 work on 32 bit platforms)

The second point would certainly be "dead code", but would help in the future to embed further patches against the OCaml distribution.

Thanks for your great job of cutting opam releases and your work on opam! :D