diff --git a/ChangeLog b/ChangeLog
index ccc150821d..c4c74d65fb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed Oct 13 05:23:04 2010  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* missing/strchr.c: add strlen's prototype.
+
+	* missing/strtrr.c: ditto.
+
 Wed Oct 13 00:21:17 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/syck/rubyext.c (struct mktime_arg): constified.
diff --git a/missing/strchr.c b/missing/strchr.c
index 719a1be8be..465f07b61e 100644
--- a/missing/strchr.c
+++ b/missing/strchr.c
@@ -2,6 +2,8 @@
 
 #include "ruby/missing.h"
 
+size_t strlen(const char*);
+
 char *
 strchr(const char *s, int c)
 {
diff --git a/missing/strstr.c b/missing/strstr.c
index cd2a4a4d5e..e6613c5d2f 100644
--- a/missing/strstr.c
+++ b/missing/strstr.c
@@ -2,6 +2,8 @@
 
 #include "ruby/missing.h"
 
+size_t strlen(const char*);
+
 char *
 strstr(const char *haystack, const char *needle)
 {