old warning in docs

Given that we have not supported releases older than 8.3 for quite a 
while, do we need to keep this in extend.sgml any longer?
  <caution>    <para>     Changing <varname>PG_CONFIG</varname> only works when building     against
<productname>PostgreSQL</productname>8.3 or later.     With older releases it does not work to set it to anything
except    <literal>pg_config</>; you must alter your <varname>PATH</>     to select the installation to build against.
 </para>   </caution>
 

cheers

andrew