functions set or get pthread_rwlock type, current supported types are: PTHREAD_RWLOCK_PREFER_READER_NP, PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP, PTHREAD_RWLOCK_PREFER_WRITER_NP, default is PTHREAD_RWLOCK_PREFER_WRITER_NONCECURSIVE_NP, this maintains binary compatible with old code.