if(NOT HAVE_CLOCK_GETTIME)
check_library_exists(c clock_get_time "mach/time.h" HAVE_CLOCK_GET_TIME)
if(NOT HAVE_CLOCK_GET_TIME)
if(NOT HAVE_CLOCK_GETTIME)
check_library_exists(c clock_get_time "mach/time.h" HAVE_CLOCK_GET_TIME)
if(NOT HAVE_CLOCK_GET_TIME)