Better DSO flags recognition on NetBSD platforms using ELF.

Submitted by: Todd Vierling <tv@pobox.com>
Reviewed by: Ralf S. Engelschall
PR: 4310


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@83213 13f79535-47bb-0310-9956-ffa450edef68