ITS#9861 fix readonly regression from #9017

libraries/liblmdb/mdb.c

@@ -6074,9 +6074,11 @@ mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode
 		/* Synchronous fd for meta writes. Needed even with
 		 * MDB_NOSYNC/MDB_NOMETASYNC, in case these get reset.
 		 */
-		rc = mdb_fopen(env, &fname, MDB_O_META, mode, &env->me_mfd);
-		if (rc)
-			goto leave;
+		if (!(flags & (MDB_RDONLY|MDB_WRITEMAP))) {
+			rc = mdb_fopen(env, &fname, MDB_O_META, mode, &env->me_mfd);
+			if (rc)
+				goto leave;
+		}
 		DPRINTF(("opened dbenv %p", (void *) env));
 		if (excl > 0 && !(flags & MDB_PREVSNAPSHOT)) {
 			rc = mdb_env_share_locks(env, &excl);