Add fix for RT #71271.

Add fix for RT #71271.

Seems that my utimens() addition inspired someone to notice the
lack of support in other codepaths for sub-second time resolution.
This fix takes the fractional portion of any mtime/ctime/atime
values and converts it into the appropriate nanosecond value, and
assigns that to the correct location in the "struct stat". Tested
on Linux 3.0 (Ubuntu 11.10), FreeBSD 8.2, NetBSD 5.1 and MacOS X
10.6 (Snow Leopard).