bug#6524: du now uses less than half as much memory, sometimes

[Paul Eggert]

On 07/07/10 03:03, Jim Meyering wrote:
> I prefer to use unsigned types when appropriate,
> and adjusted a couple of other things for readability.

Thanks, that change looks good of course (after the later
replacement of ino with dev).  I'll try to keep the preference
for unsigned in mind in later patches.