diff --git a/lib/sql-filter-variables.c b/lib/sql-filter-variables.c
index 5dd89db..ae81d10 100644
--- a/lib/sql-filter-variables.c
+++ b/lib/sql-filter-variables.c
@@ -18,6 +18,7 @@
 
  $%ENDLICENSE%$ */
 
+#include "glib-ext.h"
 #include "sql-filter-variables.h"
 #include "cetus-util.h"