ocaml-rs: Undefined reference to "caml_startup" when trying to run `dune utop`

In an ocaml-rs project, for example ocaml-rust-starter, running dune utop gives the following error (while linking):

/usr/bin/ld: src/libocaml_rust_starter.a(ocaml_interop-4a398e80f3ca6ceb.ocaml_interop.8eq22uyz-cgu.12.rcgu.o): in function `_ZN3std4sync4once4Once9call_once28_$u7b$$u7b$closure$u7d$$u7d$17h7171c1b9a6fc7898E.llvm.3140953836603515050':
ocaml_interop.8eq22uyz-cgu.12:(.text._ZN3std4sync4once4Once9call_once28_$u7b$$u7b$closure$u7d$$u7d$17h7171c1b9a6fc7898E.llvm.3140953836603515050+0x3b): undefined reference to `caml_startup'
/usr/bin/ld: src/libocaml_rust_starter.a(ocaml_interop-4a398e80f3ca6ceb.ocaml_interop.8eq22uyz-cgu.12.rcgu.o): in function `_ZN4core3ops8function6FnOnce40call_once$u7b$$u7b$vtable.shim$u7d$$u7d$17h59471d095cabe6c5E.llvm.3140953836603515050':
ocaml_interop.8eq22uyz-cgu.12:(.text._ZN4core3ops8function6FnOnce40call_once$u7b$$u7b$vtable.shim$u7d$$u7d$17h59471d095cabe6c5E.llvm.3140953836603515050+0x3b): undefined reference to `caml_startup'
collect2: error: ld returned 1 exit status

Adding this function somewhere where the linker sees it, for example using the following code, “fixes” the issue and utop starts fine:

#[ocaml::func]
pub fn caml_startup() {}

OCaml version: 4.11.1 Rust version: nightly GCC version: 10.2.0