Make state saving optional: this will allow to build SLIRP without
QEMU. (eventually, the vmstate helpers will be extracted, so an
external project & process could save its state)
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Marc-André Lureau