[eigen] making doc - what am I missing?

[Helmut Jarausch <jarausch@xxxxxxxxxxxxxxxxxxx>]

Hi,

I'm using Eigen trunk.
Given /OBJ/Math/Eigen contains a copy of the HG-eigen folder.
To build the documentation I have tried

mkdir /OBJ/Math/Eigen_Build
cd /OBJ/Math/Eigen_Build
cmake -G "Unix Makefiles" ../Eigen/
make
make -j4 doc

But, when looking into doc/html/index.html
it starts with

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{doxygen}

% Packages used by this style file
\RequirePackage{alltt}
\RequirePackage{array}
\RequirePackage{calc}
....
only lateron, following line 387 there is  (there is no <script> 
preceding this:)

</script>
<div class="navigation" id="top">
  <div class="tabs">
    <ul class="tablist">
      <li class="current"><a href="index.html"><span>Main&nbsp;Page</
span></a></li>
      <li><a href="pages.html"><span>Related&nbsp;Pages</span></a></li>
      <li><a href="modules.html"><span>Modules</span></a></li>
      <li><a href="annotated.html"><span>Classes</span></a></li>
    </ul>
  </div>
</div>
......

What am I missing? ( I have a bleeding edge Gentoo system running 
here )

Many thanks for a hint,
Helmut.