1 files changed, 1 insertions, 0 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 087bd750b04..4507af6e6bb 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -1611,6 +1611,7 @@ EXFUN (Fread_non_nil_coding_system, 1);
 EXFUN (Ffind_operation_coding_system, MANY);
 EXFUN (Fencode_coding_string, 3);
 EXFUN (Fdecode_coding_string, 3);
+extern Lisp_Object detect_coding_system P_ ((unsigned char *, int, int));
 
 /* Defined in charset.c */
 EXFUN (Fchar_bytes, 1);