message: change order of flags
diff: namespace cmdstan {
  void write_stan_flags(stan::callbacks::writer &writer) {
  -#ifdef STAN_OPENCL
  - writer("STAN_OPENCL=true");
  -#else
  - writer("STAN_OPENCL=false");
  -#endif
  #ifdef STAN_THREADS
  writer("STAN_THREADS=true");
  #else
  @@ -22,6 +17,11 @@ void write_stan_flags(stan::callbacks::writer &writer) {
  #else
  writer("STAN_MPI=false");
  #endif
  +#ifdef STAN_OPENCL
  + writer("STAN_OPENCL=true");
  +#else
  + writer("STAN_OPENCL=false");
  +#endif
  #ifdef STAN_NO_RANGE_CHECKS
  writer("STAN_NO_RANGE_CHECKS=true");
  #else
  