[PATCH roland/bz14743] BZ#14743: Move clock_* symbols from librt to libc.

[Roland McGrath]

> Probably one thing to note as a future cleanup is to fix all the test
> cases that link librt just to get clock_gettime.  I think there are a
> number of nptl test cases like that.

I've committed the change now, and rolled this cleanup into it.


Thanks,
Roland