src/support/apxs.pl: re-arranged things to handle DSO extensions

in a less hardcoded way. (.so) because the shared building chain would
fail for Cygwin which uses native Win32 extensions (.dll).

Submitted by:	Stipe Tolj <tolj@wapme-systems.de>


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@94950 13f79535-47bb-0310-9956-ffa450edef68