[bug#45133] Add ocaml reactiveData

[divoplade]

Hello,

Le mercredi 09 décembre 2020 à 14:12 -0500, Julien Lepiller a écrit :
> The ocaml-build-system will use the Makefile if it exists, 

The Makefile exists, but it is only partial (no install command).

> otherwise it runs opam-install -i --prefix=out --
> libdir=out/lib/ocaml/site-lib

If I delete the makefile in a snippet, the ocaml-build-system will not
pass "native=true" to the pkg/build.ml script, so it fails. That's why
there's a Makefile.

If I replace my install command with opam-install, I get that opam-
install does not exist (I have opam in inputs and native-inputs). Are
you sure that this program exists? I don't see it in the opam package.