Merge r486320 from trunk:

* Handle request bodies larger than 2 GB by converting the Content-Length
  header string of the request correctly to apr_off_t.

PR: 40883

Submitted by: rpluem
Reviewed by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@509665 13f79535-47bb-0310-9956-ffa450edef68