title: fortran undefined reference to popcnt_
body: <p>i am trying to compile a fortran 90 program which has a call to POPCNT as follows:</p>
  
  <pre><code> ...
   print *, popcnt(127)
   ...
  </code></pre>
  
  <p>by compiling it as follows:</p>
  
  <pre><code> gfortran prog.f90 
  </code></pre>
  
  <p>it gives me the following:</p>
  
  <pre><code> ...: undefined reference to `popcnt_'
  </code></pre>
  
  <p>plz can anyone suggest the correct way of compiling? thanks.</p>