--- a/configure.in
+++ b/configure.in
@@ -25,7 +25,7 @@ recommended.  You can remove the check f
 your responsibility whether the result works or not.])])
 AC_COPYRIGHT([Copyright (c) 1996-2015, PostgreSQL Global Development Group])
 AC_CONFIG_SRCDIR([src/backend/access/common/heaptuple.c])
-AC_CONFIG_AUX_DIR(config)
+AC_CONFIG_AUX_DIR([config])
 AC_PREFIX_DEFAULT(/usr/local/pgsql)
 AC_SUBST(configure_args, [$ac_configure_args])
 
