Made Ant build file be more specific about libraries on its classpath when compiling.

build.xml

@@ -17,7 +17,10 @@
     <javac srcdir="${src.dir}" deprecation="true" includeantruntime="true" destdir="${build.dir}" debug="true">
       <classpath>
         <fileset dir="${lib.dir}">
-          <include name="*.jar"/>
+          <include name="truezip.jar" />
+          <include name="jnbt.jar" />
+          <include name="Minecraft_Mod.jar" />
+          <include name="minecraft_server.jar" />
         </fileset>
       </classpath>
     </javac>