Add DSO support for UnixWare 7 platform.

PS: Actually I merged all UnixWare DSO cases into one because DSO
linker/compiler flags for all UnixWare 2.x and 7.x versions are identical.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@82301 13f79535-47bb-0310-9956-ffa450edef68