diff --git a/ChangeLog b/ChangeLog
index 3f4eb0da25..7fe83b60cc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Tue Dec 31 20:16:37 2002  Akinori MUSHA  <knu@iDaemons.org>
+
+	* ext/socket/addrinfo.h (NI_MAXHOST): Define NI_MAXHOST and
+	  NI_MAXHOST only if they are not defined yet.  This fixes build
+	  such platforms as OpenBSD.
+
 Tue Dec 31 20:07:49 2002  Akinori MUSHA  <knu@iDaemons.org>
 
 	* ext/tcltklib/extconf.rb (find_tcl, find_tk): Look for both
diff --git a/ext/socket/addrinfo.h b/ext/socket/addrinfo.h
index 5beea2cec6..a22615ee00 100644
--- a/ext/socket/addrinfo.h
+++ b/ext/socket/addrinfo.h
@@ -115,8 +115,10 @@
 /*
  * Constants for getnameinfo()
  */
+#ifndef NI_MAXHOST
 #define	NI_MAXHOST	1025
 #define	NI_MAXSERV	32
+#endif
 
 /*
  * Flag values for getnameinfo()