diff --git a/src/proto/charset.pro b/src/proto/charset.pro
index 4b6890d..ff0c45c 100644
--- a/src/proto/charset.pro
+++ b/src/proto/charset.pro
@@ -21,6 +21,7 @@
 int vim_iswordp __ARGS((char_u *p));
 int vim_iswordc_buf __ARGS((char_u *p, buf_T *buf));
 int vim_isfilec __ARGS((int c));
+int vim_isfilec_or_wc __ARGS((int c));
 int vim_isprintc __ARGS((int c));
 int vim_isprintc_strict __ARGS((int c));
 int lbr_chartabsize __ARGS((unsigned char *s, colnr_T col));