[compiler-hacking] Use of opam-compiler-conf: install packages

[Olivier Nicole]

Hello,

I switched to a modified version of OCaml using Gabriel Scherer's
opam-compiler-conf script. But when I try to install the core package, I
get a version error:

> $ ocaml -version
> The OCaml toplevel, version 4.04.0+dev0-2016-02-18
> $ opam install core
> [ERROR] core is not available because your system doesn't comply with ocaml-version
>         >= "4.02.1" & ocaml-version < "4.03".

Is there any clean way to install packages with a modified version of
the compiler?

Thanks,

Olivier