XBOX/i386 and xlint removal

[Konstantin Belousov]

On Thu, Nov 09, 2017 at 03:52:21PM +0200, Konstantin Belousov wrote:
> Hello,
> I created two reviews to axe two features which I personally find of
> little use in modern FreeBSD.

...

I put the follow up to remove the lint support from the headers.
Feel free to review and comment, after adding yourself as reviewer.

https://reviews.freebsd.org/D13156

Only include/ include/sys and x86 are handled.