Add TCP_REPAIR_WINDOW from Linux 4.8

[Joseph Myers]

On Mon, 3 Oct 2016, Carlos O'Donell wrote:

> And double check it doesn't need coordination if you might ever want
> to include the UAPI header and the glibc header.

Since both headers already have many of the same structures without any 
conditionals on them, I don't think adding a new structure indicates doing 
anything new regarding coordination.

-- 
Joseph S. Myers
joseph@codesourcery.com