title: Invalid directive: '%baseclass-preinclude' with Bison
body: <p>I would like to compile a parser with bison, that has these line at the top:</p>
  <pre><code>%language &quot;c++&quot;
  %baseclass-preinclude &lt;iostream&gt;
  %lsp-needed
  </code></pre>
  <p>Unfortunately I get this error:</p>
  <pre><code>parser.y:2.1-21: error: invalid directive: '%baseclass-preinclude'
      2 | %baseclass-preinclude &lt;iostream&gt;
        | ^~~~~~~~~~~~~~~~~~~~~
  parser.y:3.1-11: error: invalid directive: '%lsp-needed'
      3 | %lsp-needed
        | ^~~~~~~~~~~
  </code></pre>
  <p>I have <code>bison (GNU Bison) 3.8.2</code> running on Windows
  I am not able to find anything useful related to <code>baseclass-preinclude</code>. It was used in an example parser in a tutorial, that I try to reproduce</p>
  <p>I run it like this:</p>
  <pre><code>bison parser.y
  </code></pre>