I've installed core using opam, added opam config to the bash environment,
but I can't compile a program using the core module (the module is installed):
$ opam install core
[NOTE] Package core is already installed (current version is 113.33.03).
$ ocamlfind ocamlopt -o progprog -linkpkg -package core test1.ml
ocamlfind: Package `core' not found
If I do ocamlfind list I can't see the package (core) in the list.
What could be the reason?