diff --git a/src/proto/buffer.pro b/src/proto/buffer.pro
index 9da8c3e..d0556b6 100644
--- a/src/proto/buffer.pro
+++ b/src/proto/buffer.pro
@@ -10,6 +10,7 @@
 extern int do_buffer __ARGS((int action, int start, int dir, int count, int forceit));
 extern void set_curbuf __ARGS((buf_T *buf, int action));
 extern void enter_buffer __ARGS((buf_T *buf));
+extern void do_autochdir __ARGS((void));
 extern buf_T *buflist_new __ARGS((char_u *ffname, char_u *sfname, linenr_T lnum, int flags));
 extern void free_buf_options __ARGS((buf_T *buf, int free_p_ff));
 extern int buflist_getfile __ARGS((int n, linenr_T lnum, int options, int forceit));