OCaml with MSYS2 on Windows: Unbound module stdlib

I have just installed ocaml on MSYS2 with the command

pacman -S mingw-w64-x86_64-ocaml

Then running

ocaml -version

gives me the output 4.14.0

I wrote my first program, which looks like

//bonjour.mlprint_string "Bonjour Florian!";

When I save it and compile it with the command

ocaml -o bonjour.exe bonjour.ml

the error message is

File "command line", line 1:Error: Unbound module Stdlib

What can I do about this problem? I would really like to work with an installation of ocaml with MSYS2.