Update netinet/tcp.h from Linux 4.18

[Florian Weimer]

On 08/20/2018 10:21 PM, Joseph Myers wrote:
> +/* For use with TCP_ZEROCOPY_RECEIVE.  */
> +struct tcp_zerocopy_receive
> +{
> +  uint64_t address; /* In: address of mapping.  */
> +  uint32_t length; /* In/out: number of bytes to map/mapped.  */
> +  uint32_t recv_skip_hint; /* Out: amount of bytes to skip.  */
> +};

Works for me.

Thanks,
Florian