/tt></p>
<p> </p>
</div><p>Returns the <code>.erl</code> file extension if <code>erl</code> option is set, otherwise
  <code>.beam</code>.</p>

<h3 class="function"><a name="include_opt-1">include_opt/1</a></h3>
<div class="spec">
<p><tt>include_opt(Opts::<a href="#type-options">options()</a>) -&gt; Dir::string()</tt><br></p>
<p> </p>
</div><p>Returns the compiler include directory option if defined. Defaults
  to '.'.</p>

<h3 class="function"><a name="out_dir_opt-1">out_dir_opt/1</a></h3>
<div class="spec