Backport from 2.1:

Prevent the server from crashing when entering infinite loops. The
new LimitInternalRecursion directive configures limits of subsequent
internal redirects and nested subrequests, after which the request
will be aborted.  PR 19753 (and probably others).

Reviewed by: Andre Malo, Brian Pane, Justin Erenkrantz


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/APACHE_2_0_BRANCH@100426 13f79535-47bb-0310-9956-ffa450edef68