There are some explicit Send/Sync implementations for Window's types
that don't exist in Unix. While the end result will be the same, I
believe it's clearer if we keep the explicit implementations consistent
by making the os-specific types Send/Sync where needed and possible.
This commit addresses tcp. Existing differences below:
src/libstd/sys/unix/tcp.rs
unsafe impl Sync for TcpListener {}
unsafe impl Sync for AcceptorInner {}
src/libstd/sys/windows/tcp.rs
unsafe impl Send for Event {}
unsafe impl Sync for Event {}
unsafe impl Send for TcpListener {}
unsafe impl Sync for TcpListener {}
unsafe impl Send for TcpAcceptor {}
unsafe impl Sync for TcpAcceptor {}
unsafe impl Send for AcceptorInner {}
unsafe impl Sync for AcceptorInner {}
fde4472848