title: Does doxygen predefine any macros?
body: <p>Apart from the <code>PREDEFINED</code> configuration option, where I could always put <code>DOXYGEN=1</code>, does doxygen predefine any preprocessor macros prior to reading C++ files?</p>
  
  <p>My train of thought is that GCC predefines macros such as <code>__GNUC__</code>, and MSC predefines macros such as <code>_MSC_VER</code>. Does doxygen predefine macros at all, such as <code>_DOXYGEN_VER</code>?</p>
  
  <p>I don't want to use the <code>PREDEFINED</code> configuration option at all.</p>