#elif defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_CONF)
nproc = sysconf(_SC_NPROCESSORS_CONF);
#elif defined(darwin_HOST_OS)
#elif defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_CONF)
nproc = sysconf(_SC_NPROCESSORS_CONF);
#elif defined(darwin_HOST_OS)