back out Ken's recent patch, I'm vetoing it:

- it adds a new API which can only be implemented through O(n^2) methods
- it does not solve the problem in a way which is compatible with existing
  modules
- We went over this, and other solutions were presented.  The current
  situation is already O(n^2), so I'm not just vetoing this based on that
  -- I'm vetoing this because I don't want another O(n^2) API embedded
  into the code.  A solution which would retain more compatibility with
  existing modules would add an "table *vary" to the request_rec, and
  then modify ap_send_http_header to merge the contents of the table
  and any "Vary" entry in r->headers_out.  This can be done with a simple
  sort operation.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@83523 13f79535-47bb-0310-9956-ffa450edef68