diff --git a/ChangeLog b/ChangeLog
index ee58a2dea5..de1c8443df 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Mon Nov 23 16:06:53 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* thread_pthread.c (RUBY_STACK_MIN, RUBY_STACK_SPACE): delay for
+	  platforms where PTHREAD_STACK_MIN is not compile time constant.
+	  [ruby-dev:39751]
+
 Mon Nov 23 11:26:45 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* dln.c (dln_find_1): removed duplication.
diff --git a/thread_pthread.c b/thread_pthread.c
index c8ee4e1272..0d37a12130 100644
--- a/thread_pthread.c
+++ b/thread_pthread.c
@@ -463,16 +463,18 @@ enum {
 #else
     RUBY_STACK_MIN_LIMIT = 512 * 1024, /* 512KB */
 #endif
-    RUBY_STACK_MIN = (
-#ifdef PTHREAD_STACK_MIN
-	(RUBY_STACK_MIN_LIMIT < PTHREAD_STACK_MIN) ? PTHREAD_STACK_MIN * 2 :
-#endif
-	RUBY_STACK_MIN_LIMIT),
-    RUBY_STACK_SPACE_LIMIT = 1024 * 1024,
-    RUBY_STACK_SPACE = (RUBY_STACK_MIN/5 > RUBY_STACK_SPACE_LIMIT ?
-			RUBY_STACK_SPACE_LIMIT : RUBY_STACK_MIN/5)
+    RUBY_STACK_SPACE_LIMIT = 1024 * 1024
 };
 
+#ifdef PTHREAD_STACK_MIN
+#define RUBY_STACK_MIN ((RUBY_STACK_MIN_LIMIT < PTHREAD_STACK_MIN) ? \
+			PTHREAD_STACK_MIN * 2 : RUBY_STACK_MIN_LIMIT)
+#else
+#define RUBY_STACK_MIN (RUBY_STACK_MIN_LIMIT)
+#endif
+#define RUBY_STACK_SPACE (RUBY_STACK_MIN/5 > RUBY_STACK_SPACE_LIMIT ? \
+			  RUBY_STACK_SPACE_LIMIT : RUBY_STACK_MIN/5)
+
 static int
 native_thread_create(rb_thread_t *th)
 {