Merge r1529554 from trunk:

APR DSOs have .dll extension on Cygwin too.

PR: 55587
Submitted by: Carlo Bramini <carlo.bramix libero.it>


git-svn-id: https://svn.apache.org/repos/asf/apr/apr-util/branches/1.5.x@1529675 13f79535-47bb-0310-9956-ffa450edef68