Cannot Create Socket Networking in Windows Host using Multicast

Hello QEMU devs,

I am trying to create a simulated VLAN using socket networking, and the only way to connect multiple networks in QEMU using socket networking is by using the multicast `mcast` option of the `socket` network backend.

However, when I try use the following arguments in QEMU to create a multicast socket network:

`-device e1000,id=sock-0 -netdev id=sock-0,mcast=230.0.0.1:1234`

it fails with:

`can't bind ip address=230.0.0.1: unknown error` in my Windows host.

I would like to know if this is a bug, or if I am missing a prerequisite before running the QEMU command.