Approxidate!

@tcr 
So I lied. What we're actually going to need to say here is:

```
This code was taken from git's source. Permission has been explicitly given by its author (David Woodhouse) for use in LGPL and BSD-licensed projects[1][2][3]. Any modifications carry the original license of the file.

[1] David Woodhouse: http://www.gelato.unsw.edu.au/archives/git/0610/29021.html
[2] Linus Torvalds: http://www.gelato.unsw.edu.au/archives/git/0610/28969.html
[3] Junio C Hamano: http://www.gelato.unsw.edu.au/archives/git/0610/28978.html
```