diff --git a/src/sql/mdbsql.c b/src/sql/mdbsql.c
index 9957b07..d545345 100644
--- a/src/sql/mdbsql.c
+++ b/src/sql/mdbsql.c
@@ -17,9 +17,8 @@
  */
 
 #include <stdarg.h>
-#include <locale.h>
 #ifndef _XOPEN_SOURCE
-#define _XOPEN_SOURCE 600
+#define _XOPEN_SOURCE 700
 #endif
 #include "mdbsql.h"
 
@@ -28,6 +27,8 @@
 #include <stdio.h>
 #endif
 
+#include <locale.h>
+
 /** \addtogroup mdbsql
  *  @{
  */