diff --git a/ChangeLog b/ChangeLog
index 669738deb9..ed8ce494fa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Jan  6 17:22:41 2005  Hirokazu Yamamoto  <ocean@m2.ccsnet.ne.jp>
+
+	* random.c (random_seed): O_NONBLOCK isn't defined on some
+	  platforms. [ruby-dev:25417]
+
 Thu Jan  6 13:45:35 2005  Tanaka Akira  <akr@m17n.org>
 
 	* lib/time.rb: recognize +00:00 and GMT as a localtime.
diff --git a/random.c b/random.c
index b069c1dc89..6a4ed2d286 100644
--- a/random.c
+++ b/random.c
@@ -275,7 +275,10 @@ random_seed()
     memset(digits, 0, big->len * SIZEOF_BDIGITS);
 
 #ifdef S_ISCHR
-    if ((fd = open("/dev/urandom", O_RDONLY|O_NONBLOCK
+    if ((fd = open("/dev/urandom", O_RDONLY
+#ifdef O_NONBLOCK
+            |O_NONBLOCK
+#endif
 #ifdef O_NOCTTY
             |O_NOCTTY
 #endif