title: Generate multiple target using single action/rule
body: <p>How do I write a rule to generate set of files using a single action.</p>
  
  <p>Example:
  Files <code>x</code>, <code>y</code>, <code>z</code> are generated as a result of single execution of script <code>t.sh</code> which takes file <code>a</code> as input.</p>
  
  <pre><code>x y z: a
      t.sh $@
  </code></pre>
  
  <p>GNU make tries to execute <code>t.sh</code> 3 times.</p>