HAVE_PRAGMA_WEAK_REF
#ifdef HAVE_PRAGMA_WEAK_REF
#ifdef HAVE_PRAGMA_WEAK_REF
# ifndef HAVE_PRAGMA_WEAK_REF
#ifdef HAVE_PRAGMA_WEAK_REF
#if defined(DEBUG_THREADS_SLOW) && HAVE_SCHED_H && (HAVE_SCHED_YIELD || HAVE_PRAGMA_WEAK_REF)