diff --git a/libraries/liblmdb/lmdb.h b/libraries/liblmdb/lmdb.h
index ea95ecc..a8818ab 100644
--- a/libraries/liblmdb/lmdb.h
+++ b/libraries/liblmdb/lmdb.h
@@ -519,7 +519,7 @@ int  mdb_env_create(MDB_env **env);
 	 *	<li>#MDB_ROBUST
 	 *		Initialize the lockfile to catch stale locks if robust mutexes
 	 *		are supported, so aborted processes will not block others.
-	 *		Ignored when another process has the environment open, and
+	 *		Ignored when another process has the environment open. Unsupported
 	 *		by liblmdb built with MDB_USE_POSIX_SEM (such as BSD systems).
 	 *		Enabled by default on Windows. Some locking slowdown on Unix.
 	 *	<li>#MDB_WRITEMAP
diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index 98d67b8..de5b936 100644
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -4389,7 +4389,7 @@ fail:
 	 *	environment and re-opening it with the new flags.
 	 */
 #define	CHANGEABLE	(MDB_NOSYNC|MDB_NOMETASYNC|MDB_MAPASYNC|MDB_NOMEMINIT)
-#define	CHANGELESS	(MDB_FIXEDMAP|MDB_NOSUBDIR|MDB_RDONLY|MDB_ROBUST| \
+#define	CHANGELESS	(MDB_FIXEDMAP|MDB_NOSUBDIR|MDB_RDONLY|ROBUST_FLAG| \
 	MDB_WRITEMAP|MDB_NOTLS|MDB_NOLOCK|MDB_NORDAHEAD)
 
 #if VALID_FLAGS & PERSISTENT_FLAGS & (CHANGEABLE|CHANGELESS)