diff -x '.*Store' -x build.properties -Nur openjdk/langtools/make/build.xml openjdk.new/langtools/make/build.xml
--- openjdk/langtools/make/build.xml	2007-10-12 00:47:30.000000000 -0700
+++ openjdk.new/langtools/make/build.xml	2007-10-14 22:43:25.000000000 -0700
@@ -717,10 +717,11 @@
                         </not>
                     </condition>
                 </fail>
+		<available file="${@{property}}/@{marker}" property="${@{property}}.marker"/>
                 <fail message="@{name} is not installed in ${@{property}}">
                     <condition>
                         <not>
-                            <available file="${@{property}}/@{marker}"/>
+                            <isset property="${@{property}}.marker"/>
                         </not>
                     </condition>
                 </fail>