title: Print timestamp in makefile
body: <p>I want to measure the time for each of build item in make file, i just try below, why does it not work? </p>
  
  <pre>
  mytest:
      $(info 'Now time is $(date --iso=seconds)')
  </pre>
  
  <p>The date is not printed, just printed <pre>'Now time is '</pre>. What can be wrong?</p>
  
  <p><code>make --version
  GNU Make 3.81
  </code></p>