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.

pkgs/build-support/rust/build-rust-crate/default.nix

@@ -23,7 +23,7 @@ let
             lib.strings.replaceStrings ["-"] ["_"] crateRenames.${dep.crateName}
           else
             extern;
-        in (if lib.any (x: x == "lib") dep.crateType then
+        in (if lib.any (x: x == "lib" || x == "rlib") dep.crateType then
            " --extern ${name}=${dep.lib}/lib/lib${extern}-${dep.metadata}.rlib"
          else
            " --extern ${name}=${dep.lib}/lib/lib${extern}-${dep.metadata}${stdenv.hostPlatform.extensions.sharedLibrary}")