diff --git a/ChangeLog b/ChangeLog
index 52c40c5f1e..bcd5ed784b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Tue May  5 11:29:07 2009  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* tool/ifchange: Fix: arguments which begin with minus sign may
+	  parsed as options.  Because of older systems, don't use --
+	  but use parentheses.
+
 Tue May  5 10:42:28 2009  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* ext/json: Update to JSON 1.1.4.
diff --git a/tool/ifchange b/tool/ifchange
index 7038615d43..177ce7340b 100755
--- a/tool/ifchange
+++ b/tool/ifchange
@@ -8,7 +8,7 @@ until [ "$0" = 0 ]; do
 	    timestamp=.
 	    ;;
 	--timestamp=*)
-	    timestamp=`expr "$1" : '[^=]*=\(.*\)'`
+	    timestamp=`expr \( "$1" : '[^=]*=\(.*\)' \)`
 	    ;;
 	*)
 	    break