diff --git a/ChangeLog b/ChangeLog
index 64884caa41..08cce0247e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Jan 19 14:31:59 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* thread.c (rb_thread_execute_interrupts): needs
+	  rb_signal_buff_size to be declared.
+
 Mon Jan 19 13:34:25 2009  Koichi Sasada  <ko1@atdot.net>
 
 	* ruby.c (require_libraries): reset th->parse_in_eval while
diff --git a/thread.c b/thread.c
index 9996d6a4ae..b83c9495ed 100644
--- a/thread.c
+++ b/thread.c
@@ -69,6 +69,7 @@ static int rb_thread_dead(rb_thread_t *th);
 
 static void rb_check_deadlock(rb_vm_t *vm);
 
+int rb_signal_buff_size(void);
 void rb_signal_exec(rb_thread_t *th, int sig);
 void rb_disable_interrupt(void);
 void rb_thread_stop_timer_thread(void);
diff --git a/thread_pthread.c b/thread_pthread.c
index 72f8a2f288..3e368c6a6b 100644
--- a/thread_pthread.c
+++ b/thread_pthread.c
@@ -741,8 +741,6 @@ get_ts(struct timespec *ts, unsigned long nsec)
     return ts;
 }
 
-int rb_signal_buff_size(void);
-
 static void *
 thread_timer(void *dummy)
 {