diff --git a/ChangeLog b/ChangeLog
index 27a77eaba1..48aaff0786 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Tue May 14 03:10:59 2013  Koichi Sasada  <ko1@atdot.net>
+
+	* include/ruby/ruby.h: enable RGENGC (USE_RGENGC)
+	  but no type creates write protected (sunny) objects
+	  (RGENGC_WB_PROTECTED_* == 0).
+
 Tue May 14 02:47:30 2013  Koichi Sasada  <ko1@atdot.net>
 
 	* gc.c: support RGENGC. [ruby-trunk - Feature #8339]
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index 1d37b8daa3..6cebdcbc60 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -682,7 +682,7 @@ VALUE rb_obj_setup(VALUE obj, VALUE klass, VALUE type);
 } while (0)
 
 #ifndef USE_RGENGC
-#define USE_RGENGC 0
+#define USE_RGENGC 1
 #endif
 
 #ifndef RGENGC_WB_PROTECTED_ARRAY