Pick up fix from 2.1:

Fix critical bug in new --enable-v4-mapped configure option
implementation which broke IPv4 listening sockets on some
systems.

Submitted by:	hiroyuki hanai <hanai@imgsrc.co.jp>


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/APACHE_2_0_BRANCH@97755 13f79535-47bb-0310-9956-ffa450edef68