Set SO_EXCLUSIVEADDRUSE on Win32 sockets.

[DrPizza]

SO_EXCLUSIVEADDRUSE and SO_REUSEADDR are a mess on Windows. The only real way to allow a libuv server to behave consistently and robustly (i.e. to ensure that it can actually listen on the port it needs to listen on and can't get clobbered by other programs) is to set SO_EXCLUSIVEADDRUSE. I think libuv should set this for such sockets, probably for both TCP and UDP.

[bnoordhuis]

That's the plan for (at least) UDP sockets.