diff --git a/ChangeLog b/ChangeLog
index 0f5c603315..e6e8ce9a9e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Wed Feb 19 11:39:41 2014  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* configure.in: it must see rb_cv_broken_memmem not rb_cv_func_memmem.
+
 Tue Feb 18 23:18:41 2014  SHIBATA Hiroshi  <shibata.hiroshi@gmail.com>
 
 	* test/socket/test_socket.rb: unix socket is required by test case.
diff --git a/configure.in b/configure.in
index 0b54a518cd..ae93ea9642 100644
--- a/configure.in
+++ b/configure.in
@@ -3559,7 +3559,7 @@ main()
     rb_cv_broken_memmem=yes,
     rb_cv_broken_memmem=yes)
   ])
-  AS_CASE([$ac_cv_func_memmem],[yes],[ac_cv_func_memmem=no])
+  test x"$rb_cv_broken_memmem" = xyes && ac_cv_func_memmem=no
 fi