1 files changed, 1 insertions, 0 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 6c94e9e2be7..ef2c7b4c5d7 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -1673,6 +1673,7 @@ EXFUN (Fchar_width, 1);
 extern int chars_in_text P_ ((unsigned char *, int));
 extern int multibyte_chars_in_text P_ ((unsigned char *, int));
 extern int unibyte_char_to_multibyte P_ ((int));
+extern int multibyte_char_to_unibyte P_ ((int, Lisp_Object));
 extern Lisp_Object Qcharset;
 extern void init_charset_once P_ ((void));
 extern void syms_of_charset P_ ((void));