Show of hands, how many set USE_NSEC

How many users really build their Git with USE_NSEC=1?

I'm suspecting a status issue in jgit caused by jgit honoring a millisecond resolution on file modification timestamps, and the underlying filesystem supporting at least a 1/2 second (or finer) granularity, but C Git was built without USE_NSEC so it only honors 1 second granularity.

This can cause jgit to think a file is locally modified as the mtime has data in the tv_nsec field, but C Git set that to 0 in the index as USE_NSEC wasn't enabled at build time.

I'm trying to come up with a sane way for jgit to realize it should truncate the milliseconds out of a timestamp before it comes to the index record.