Llvm-config --system-libs is empty

I’m trying to install LLVM as a dependency for a Rust project that uses it to build CUDA kernels. The Rust build script uses llvm-config --system-libs to detect which libraries to link against, but in my Nix env that command prints nothing. (GitHub issue) Any idea why this is? I’m using a shell.nix with:

mkShell {
  buildInputs = [ pkgs.llvm ];

I saw there’s also a libllvm package so I tried that but it seemed to resolve to the same derivation and gave the same result.