Setting `java.compiler' or `build.compiler' in `build.properties' isn't enough.

--- apache-ant-1.7.1/build.xml	2008-06-27 07:05:23.000000000 +0200
+++ apache-ant-1.7.1/build.xml	2009-09-24 15:10:53.000000000 +0200
@@ -578,12 +578,7 @@
       classname="com.jcraft.jsch.Session"
       classpathref="classpath"/>
 
-    <condition property="build.compiler" value="classic">
-      <not>
-        <isset property="jdk1.3+"/>
-      </not>
-    </condition>
-    <property name="build.compiler" value="modern"/>
+    <property name="build.compiler" value="gcj"/>
 
     <!--check for XSD support in the parser-->
     <condition property="xmlschema.present">