Here is how to enable cgi on [lighttpd](http://www.lighttpd.net/) and configure it in order to execute ikiwiki.cgi wherever it is located. 

* Activate cgi by linking `/etc/lighttpd/conf-available/10-cgi.conf` into `/etc/lighttpd/conf-enabled` ([doc](http://trac.lighttpd.net/trac/wiki/Docs%3AModCGI)). 

* Create `/etc/lighttpd/conf-available/90-ikiwiki-cgi.conf` and add a line like this:

    cgi.assign = ( "ikiwiki.cgi"  => "", )

* Activate ikiwiki-cgi by linking `/etc/lighttpd/conf-available/90-ikiwiki-cgi.conf` into `/etc/lighttpd/conf-enabled`. 

* Restart lighttpd server with something like `/etc/init.d/lighttpd restart`.

Note that the first part enables cgi server wide but depending on default configuration, it may be not enough. The second part creates a specific rule that allow `ikiwiki.cgi` to be executed.

**Warning:** I only use this on my development server (offline). I am not sure of how secure this approach is. If you have any thought about it, feel free to let me know.