message: make enzyme variables extern
diff: * documentation (https://enzyme.mit.edu) for more information.
  */
  -int enzyme_dup;
  -int enzyme_dupnoneed;
  -int enzyme_out;
  -int enzyme_const;
  +extern int enzyme_dup;
  +extern int enzyme_dupnoneed;
  +extern int enzyme_out;
  +extern int enzyme_const;
  template <typename return_type, typename... Args>
  return_type __enzyme_autodiff(Args...);
  