 already
been a previous call to this command with the same output.</p>
<p>If the previous call specified the output via a generator expression,
the output specified by the current call must match in at least one
configuration after evaluating generator expressions.  In this case,
the appended commands and dependencies apply to all configurations.</p>
<p>The <code class="docutils literal notranslate"><span class="pre">COMMENT</span></code>, <code class="docutils literal notranslate"><span class="pre">MAIN_D