cmake HAVE_PTHREAD_RWLOCK_RDLOCK examples

alibaba/AliSQL configure.cmake :558 

CHECK_FUNCTION_EXISTS (pthread_rwlock_rdlock HAVE_PTHREAD_RWLOCK_RDLOCK)

arkdb/arkproxy configure.cmake :378 

CHECK_FUNCTION_EXISTS (pthread_rwlock_rdlock HAVE_PTHREAD_RWLOCK_RDLOCK)

alibaba/AliSQLBackup configure.cmake :473 

CHECK_FUNCTION_EXISTS (pthread_rwlock_rdlock HAVE_PTHREAD_RWLOCK_RDLOCK)