[ocaml-platform] issue opam-repository#10420: How to properly advertize incompatibility with `-default-safe-string`?

[Gabriel Scherer]

Dear platform,

In preparation for the 4.06 release, I am wondering whether there is a
proper way to mark packages as incompatible with -default-safe-string,
but still work (and can be tested) under 4.06 when using
-default-unsafe-string:

  https://github.com/ocaml/opam-repository/issues/10420

Any input is welcome.