how to compile and use soundex

Hi,

in the directory contrib I found soundex.c and soundex.sql. How 
I can compile or use the soundex-function?

Is there any documentation about this topic. I didn't find any
hints in the mailing-list.

Thanks for any answer.

Christian Guenther
-- 
 Christian Guenther         http://laokoon.in-berlin.de/Kuenstler/ 
 Fax: +49 030 4464152       http://laokoon.in-berlin.de/Museum/
 Tel: +49 030 4442931       E-mail: guenther@laokoon.in-berlin.de