PORT: QNX needed a #include <sys/mman.h>; and now it uses flock

serialized accept to handle multiple sockets.

PR:             2295, 2296
Submitted by:   Rob Saccoccio <robs@InfiniteTechnology.com>


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@81397 13f79535-47bb-0310-9956-ffa450edef68