[Toybox] [PATCH] tar: fix tvf for sparse extension headers.

[Rob Landley]

On 9/13/19 8:17 PM, Rob Landley wrote:
> I think what we need to do is add up the segments. (Which is what I thought it
> _was_ doing, but my head cold has turned into dizzy+headache and I has a tired.)
> 
> I can fix this when I feel better if you don't get to it.

I pushed a patch. It only calls truncate() when it hits a zero length segment
(and only when lseek() didn't fail, so writing to a nonseekable output shouldn't
gratuitously fail at the truncate), and it uses the last offset+length as a
sparse file as the display length.

I think that fixes it?

Rob