diff --git a/src/proto/eval.pro b/src/proto/eval.pro
index 7c3f7a1..8cb0dd6 100644
--- a/src/proto/eval.pro
+++ b/src/proto/eval.pro
@@ -75,6 +75,7 @@
 dictitem_T *dict_find __ARGS((dict_T *d, char_u *key, int len));
 char_u *get_dict_string __ARGS((dict_T *d, char_u *key, int save));
 long get_dict_number __ARGS((dict_T *d, char_u *key));
+void dict_extend __ARGS((dict_T *d1, dict_T *d2, char_u *action));
 char_u *get_function_name __ARGS((expand_T *xp, int idx));
 char_u *get_expr_name __ARGS((expand_T *xp, int idx));
 char_u *get_expanded_name __ARGS((char_u *name, int check));