*) regex: Allow to configure global/default options for regexes, like

     caseless matching or extended format.
     trunk patch: http://svn.apache.org/r1824339
                  http://svn.apache.org/r1824439
     +1: ylavic, rpluem, minfrin


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1824472 13f79535-47bb-0310-9956-ffa450edef68