build.xml in calabash-android-0.4.18

- old
+ new

@@ -42,9 +42,17 @@
     <target name="-check.preconditions">
       <available file="${calabashjs.dir}" type="dir" property="doesCalabashJsExist" />
       <fail unless="doesCalabashJsExist">
         ${calabashjs.dir} does not exist.
       </fail>
+      <antversion property="version.running" />
+      <fail message="FATAL ERROR:  The running Ant version, ${version.running}, is too old.">
+        <condition>
+          <not>
+            <antversion atleast="1.8" />
+          </not>
+        </condition>
+      </fail>
     </target>
 
     <target name="-stage">
       <mkdir dir="${staging.dir}"/>
       <mkdir dir="${bin.dir}"/>