diff --git a/src/proto/option.pro b/src/proto/option.pro
index 210c60a..1c7c3b2 100644
--- a/src/proto/option.pro
+++ b/src/proto/option.pro
@@ -75,4 +75,5 @@
 char_u *get_showbreak_value(win_T *win);
 dict_T *get_winbuf_options(int bufopt);
 int fill_culopt_flags(char_u *val, win_T *wp);
+int magic_isset(void);
 /* vim: set ft=c : */