[Bug libstdc++/54847] --enable-libstdcxx-time=yes doesn't find the function nanosleep() on darwin

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54847

--- Comment #39 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-10-08 17:16:13 UTC ---
Yes, but why do you want to disable it?

Why does that patch define _GLIBCXX_USE_SCHED_YIELD?
That is correctly detected anyway by configure, without any changes, as I said
in comment 30 and again in comment 37