[Libvir] [PATCH 5/8] Compile libvirt under Windows (Cygwin)

Detect if the XDR functions are in a separate library which needs `-lrpc' to link against (Cygwin for sure, probably Solaris too). Rich. -- Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/ Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 03798903