My Ikiwiki and blog has structure

    /website
    blog.mdwn
    ...

    /website/blog
    /website/blog/blog1.mdwn
    /website/blog/blog2.mdwn
    ...

After running

    ikiwiki-calendar ./foo.setup "/blog/*"

I got a

   /website/archives/

and archive pages in it.

I'd like to have it in 

   /website/blog/archives/

as those are archive pages for blog pages only.  How to do it?
