g environment variables
    </h3>

    <p>
      By default, no environment variables from the host machine are available
      to rules. To make a variable available to the rule, set the
      <code class="code">pass_env</code> parameter on
      <code class="code">genrule()</code> and
      <code class="code">gentest()</code>.
    </p>

    <p>
      These variables will be made available to both
      <code class="code">cmd</code> and <code class="code">test_cmd</code>. They
      will also contribute to