diff --git a/ChangeLog b/ChangeLog
index ed44ff519c..09ff121300 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Feb 11 19:19:21 2010  Kazuhiro NISHIYAMA  <zn@mbf.nifty.com>
+
+	* missing/alloca.c: s/RUBY_LIB/RUBY_LIB_PREFIX/ [ruby-dev:40395]
+
 Thu Feb 11 17:52:11 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* vm.c (vm_exec): reset thread state before restarting vm loop
diff --git a/missing/alloca.c b/missing/alloca.c
index 620eef12e5..d23917f3f7 100644
--- a/missing/alloca.c
+++ b/missing/alloca.c
@@ -54,7 +54,7 @@ typedef char	*pointer;		/* generic pointer type */
 
 #define	NULL	0			/* null pointer constant */
 
-#ifdef RUBY_LIB
+#ifdef RUBY_LIB_PREFIX
 #define xmalloc ruby_xmalloc
 #define xfree ruby_xfree
 #endif