Fix starvation issue on listening sockets where a short-lived

Fix starvation issue on listening sockets where a short-lived
connection on a rarely-accessed listening socket will cause a
child to hold the accept mutex and block out new connections until
another connection arrives on that rarely-accessed listening socket.
With Apache 2.x there is no performance concern about enabling the
logic for platforms which don't need it, so it is enabled everywhere
except for Win32.

Submitted by:	Jeff Trawick
Reviewed by:	Jim Jagielski, Justin Erenkrantz

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/APACHE_2_0_BRANCH@103018 13f79535-47bb-0310-9956-ffa450edef68