Fix a minor issue.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@770 6f19259b-4bc3-4df7-8a09-765794883524

Tools/Source/GenBuild/org/tianocore/build/fpd/PlatformBuildFileGenerator.java

@@ -109,6 +109,10 @@ public class PlatformBuildFileGenerator {
             ele.setAttribute("resource", "frameworktasks.tasks");
             root.appendChild(ele);
 
+            ele = document.createElement("taskdef");
+            ele.setAttribute("resource", "net/sf/antcontrib/antlib.xml");
+            root.appendChild(ele);
+            
             ele = document.createElement("property");
             ele.setAttribute("environment", "env");
             root.appendChild(ele);