diff --git a/util/ceg/defaults/not_impl/not_impl.c b/util/ceg/defaults/not_impl/not_impl.c
index 593e546ec..8391c16a5 100644
--- a/util/ceg/defaults/not_impl/not_impl.c
+++ b/util/ceg/defaults/not_impl/not_impl.c
@@ -1,4 +1,5 @@
 #include <system.h>
+#include "back.h"
 
 not_implemented( instr)
 char *instr;