2012-10-10  Jack Howarth  <howarth@bromo.med.uc.edu>
	    Jonathan Wakely  <jwakely.gcc@gmail.com>

	* config/os/bsd/darwin/os_defines.h: Define _GLIBCXX_USE_NANOSLEEP
	and _GLIBCXX_USE_SCHED_YIELD.
	* acinclude.m4 (GLIBCXX_ENABLE_LIBSTDCXX_TIME): Add comment.

Co-Authored-By: Jonathan Wakely <jwakely.gcc@gmail.com>

From-SVN: r192335