Merge r1808230 from trunk:

* server/protocol.c (ap_content_length_filter): Rewrite the content
  length filter to avoid arbitrary memory consumption for streaming
  responses (e.g. large CGI script output).  Ensures C-L is still
  generated in common cases (static content, small CGI script output),
  but this DOES change behaviour and some responses will end up
  chunked rather than C-L computed.

PR: 61222
Submitted by: jorton, rpluem
Reviewed by: jorton, wrowe, ylavic


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1811746 13f79535-47bb-0310-9956-ffa450edef68