[issue1436] gtar fails to build due to incomplete list of *at() functions

[Nicolas Thery]

2009/7/28 Simon 'corecode' Schubert (via DragonFly issue tracker)
<bugs at crater.dragonflybsd.org>:
>
> Simon 'corecode' Schubert <corecode at fs.ei.tum.de> added the comment:
>
> Nicolas Thery (via DragonFly issue tracker) wrote:
>> I implemented fstatat() on Sunday and gtar now builds fine at my end.
>
> Thanks!

Committed as 1db695af2833642e19524b6e4a3ecc73a931ee7c and
e101a3f427be0008bdb02ef35c6e820dc25056d7.