Libvirt can be compiled on Windows using the free MinGW compiler. You can also cross-compile to a Windows target from a Fedora machine using the packages available from the Fedora MinGW project (which includes a working libvirt specfile).
Libvirt can only be built as a client on Windows allowing remote access to systems libvirt servers. Configure libvirt like this:
./configure \ --without-sasl \ --without-avahi \ --without-polkit \ --without-python \ --without-xen \ --without-qemu \ --without-lxc \ --without-openvz \ --without-libvirtd
We intend to supply Windows binaries on this page later, but at the moment you have to compile from source.