title: Custom Perl target location with Module::Build
body: <p>I've customized a <code>Module::Build</code> script to install files from a <code>perllib/</code> directory in my sandbox to <code>perl/</code> in the target directory.</p>
  
  <pre><code># Install perllib
  $build-&gt;add_build_element("perllib");
  $build-&gt;install_path(perllib =&gt; "$install_base/perl");
  </code></pre>
  
  <p>When I run <code>./Build test</code>, Perl can't find the files under <code>blib/</code> because it doesn't know that that these <code>perllib</code> files belong on <code>@INC</code>.</p>
  
  <p>Is it possible to add the custom <code>perllib</code> directory to the installation, in such a way that the build system understands that they're Perl files, which should be included when we run tests?</p>