lighttpd.conf - document root as directory containing config file
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I want to use lighttpd as a development server, similar to WEBrick for Rails, or `manage.py runserver` for Django. (This is for both PHP and for learning Javascript where I can't use AJAX on the local filesystem). I also want to be able to share the result with other developers through checking in the conf file to source control along with the code, so I want paths relative to the conf file, not absolute paths that are only valid on my system.

So I saw [this answer about using lighttpd](http://stackoverflow.com/a/5438057/3189) which is very close to what I want. However, rather than having to change to the correct directory and then run the script, ideally I want to be able to do:

    lighttpd -f path/to/lighttpd.conf

and for the document root to be relative to the directory the lighttpd.conf file is in. So I want to be able to have a config line something like:

    server.document-root = dirname(__file__) + "/html"

The answer linked to above uses `CWD` for the directory, so this seems like something that might well be available. Any idea how to specify it? 

*(As a side note, can anyone link to a comprehensive reference to `lighttpd.conf` and the options available? I haven't been able to find one.)*