diff --git a/ChangeLog b/ChangeLog
index 2c52a728da..b8fcf41b79 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Wed Aug 31 06:45:32 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* configure.in: fix r32835. $withval can't be used outer AC_ARG_WITH().
+
 Wed Aug 31 05:29:03 2011  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* win32/win32.c (rb_w32_select_with_thread): and my typo. we all must
diff --git a/configure.in b/configure.in
index 66f7a9c4db..f763806b41 100644
--- a/configure.in
+++ b/configure.in
@@ -113,7 +113,7 @@ then
 fi
 AS_CASE(["$build_os"],
   [darwin11.*], [
-    test -z "$withval" && : ${CC=gcc-4.2}
+    : ${CC:=gcc-4.2}
     AS_CASE(["x$CC"],
       [xgcc-4.2|x/usr/bin/gcc-4.2], [: ${CXX=g++-4.2}],
       [xgcc|x/usr/bin/gcc],         [: ${CXX=g++}],