--- a/src/interfaces/ecpg/compatlib/informix.c
+++ b/src/interfaces/ecpg/compatlib/informix.c
@@ -15,6 +15,7 @@
 #include "pgtypes_numeric.h"
 #include "sqlca.h"
 #include "sqltypes.h"
+#include "../include/sqltypes.h"
 
 /* this is also defined in ecpglib/misc.c, by defining it twice we don't have to export the symbol */