Make AntStructure compile under 1.1.

Submitted by:	Andrew B. Sudell <asudell@acm.org>,
                <Glen_Stampoultzis@ansett.com.au>


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@267779 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/AntStructure.java

@@ -108,7 +108,7 @@ public class AntStructure extends Task {
             Enumeration enum = project.getTaskDefinitions().keys();
             while (enum.hasMoreElements()) {
                 String taskName = (String) enum.nextElement();
-                tasks.add(taskName);
+                tasks.addElement(taskName);
             }
             printTargetDecl(out, tasks);