diff --git a/ChangeLog b/ChangeLog
index f99a93a655..11d89717fb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu May 31 08:31:22 2001  Usaku Nakamura  <usa@osb.att.ne.jp>
+
+	* dln.c: #define S_ISDIR if not defined.
+
 Thu May 31 01:28:54 2001  Akinori MUSHA  <knu@iDaemons.org>
 
 	* configure.in: default --with-libc_r to `no' until the problem is
diff --git a/dln.c b/dln.c
index d2c2c78c1b..a481d806ea 100644
--- a/dln.c
+++ b/dln.c
@@ -50,6 +50,10 @@ void *xrealloc();
 #include <sys/types.h>
 #include <sys/stat.h>
 
+#ifndef S_ISDIR
+#   define S_ISDIR(m) ((m & S_IFMT) == S_IFDIR)
+#endif
+
 #ifdef HAVE_SYS_PARAM_H
 # include <sys/param.h>
 #else