message: Remove cargo +nightly flag, reinstate test in dune runtest alias
diff: (run rm -rf ./target)
  (run rm -rf ./Cargo.lock)
  (run sh -c "touch dllocamlgen_test_stubs.so")
  - (run cargo +nightly build --release)
  + (run cargo build --release)
  (run sh -c "cp ../target/release/libocamlgen_test_stubs.a ."))))
  ;; generate the OCaml bindings from rust code
  ;; rule for running the tests
  (rule
  - (alias test)
  + (alias runtest)
  (action
  (run ./ocamlgen_test.exe)))
  