[Windows] Use WSADuplicateSocket to duplicate socket handles on fork

[G4Vi]

Due to Layered Service Providers(LSPs), the socket handles are not properly duplicated by calling CreateProcess with bInheritHandles=TRUE. The duplicated handles in the child processes work for some things, but not others. For example AcceptEx on a duplicated listen socket seems to work, but then setsockopt( sAcceptSocket, SOL_SOCKET, SO_UPDATE_ACCEPT_CONTEXT, (char *)&sListenSocket, sizeof(sListenSocket) ); fails making it impossible to call getpeername or any other function not in the list in the AcceptEx remarks section: https://learn.microsoft.com/en-us/windows/win32/api/mswsock/nf-mswsock-acceptex#remarks

The problem with inherited sockets is discussed more here: https://stackoverflow.com/questions/11847793/are-tcp-socket-handles-inheritable

As we control the source for the parent and child process, it should be possible to use WSADuplicateSocket to properly pass a socket to a child process.