buildRustCrate: treat `rlib` crates just like `lib` crates
buildRustCrate: treat `rlib` crates just like `lib` crates

Both version provide `rlib` files to link against. Previously we would
try to find a matching shared library in the `lib` output.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs