Revision 1885607

Backport to 2.4:

  *) mod_proxy: common spooling code to allow mod_proxy_fgci proxy-sendcl. BZ 57087
     trunk patch: https://svn.apache.org/r1884067
                  https://svn.apache.org/r1884068
                  https://svn.apache.org/r1884069
                  https://svn.apache.org/r1884070
     2.4.x patch: http://people.apache.org/~ylavic/patches/2.4.x-mod_proxy_fcgi-sendcl-5on5.patch
                  https://github.com/apache/httpd/pull/162
     +1: ylavic, covener, minfrin
     ylavic: Long standing BZ (always send Content-Length, according to the CGI
             specs) which is addressed by reusing mod_proxy_http's spooling
             code (moved to proxy_util) in mod_proxy_fcgi. The user still needs
             to SetEnv proxy-sendcl for that (2.4 compat).