2013-07-10  Jack Howarth  <howarth@bromo.med.uc.edu>

	    PR target/57792
	    * configure.ac: Use --with-sysroot=\"`xcrun --show-sdk-path`\" on darwin13 and later.
	    * configure: Regenerated.
* gentlsoffsets: Clean up a little.
* thread.cc (semaphore::_fixup_after_fork): Report on potential problem
parameter.  Make sure that currentvalue is never zero.
(semaphore::init): Make cosmetic change.