--- jsr166/build.xml	2015/09/13 03:22:29	1.179
+++ jsr166/build.xml	2015/09/13 05:26:02	1.181
@@ -95,12 +95,13 @@
     <property name="java@{v}"       location="${jdk@{v}.home}/bin/java"/>
     <property name="javac@{v}"      location="${jdk@{v}.home}/bin/javac"/>
     <property name="javadoc@{v}"    location="${jdk@{v}.home}/bin/javadoc"/>
-    <available property="jdk@{v}.have.java.base"
+    <local name="have.java.base"/>
+    <available property="have.java.base"
       file="${jdks.home}/src/jdk@{v}/jdk/src/java.base/share/classes" type="dir"/>
     <property name="jdk@{v}src.dir" location="${jdks.home}/src/jdk@{v}/jdk/src/java.base/share/classes"
-      if:set="jdk@{v}.have.java.base"/>
+      if:set="have.java.base"/>
     <property name="jdk@{v}src.dir" location="${jdks.home}/src/jdk@{v}/jdk/src/share/classes"
-      unless:set="jdk@{v}.have.java.base"/>
+      unless:set="have.java.base"/>
     <local name="boot.jar.dir"/>
     <property name="boot.jar.dir"   location="${jdk@{v}.home}/jre/lib"/>
     <path id="bootclasspath@{v}">
@@ -529,6 +530,11 @@
 
 
   <target name="configure-compiler">
+    <fail message="ant version too old">
+      <condition>
+	<not> <antversion atleast="1.9.1"/> </not>
+      </condition>
+    </fail>
 
     <property name="unchecked.option" value="-Xlint:unchecked"/>