diff --git a/src/proto/fileio.pro b/src/proto/fileio.pro
index 816de42..52ae642 100644
--- a/src/proto/fileio.pro
+++ b/src/proto/fileio.pro
@@ -41,6 +41,7 @@
 char_u *get_augroup_name __ARGS((expand_T *xp, int idx));
 char_u *set_context_in_autocmd __ARGS((expand_T *xp, char_u *arg, int doautocmd));
 char_u *get_event_name __ARGS((expand_T *xp, int idx));
+int autocmd_supported __ARGS((char_u *name));
 int au_exists __ARGS((char_u *arg));
 int match_file_pat __ARGS((char_u *pattern, regprog_T *prog, char_u *fname, char_u *sfname, char_u *tail, int allow_dirs));
 int match_file_list __ARGS((char_u *list, char_u *sfname, char_u *ffname));