--- m4/ax_pthread.m4.org	2023-06-23 14:55:01.982614710 +1000
+++ m4/ax_pthread.m4	2023-06-23 14:57:25.091174760 +1000
@@ -302,36 +302,6 @@
                                   [Define to necessary symbol if this constant
                                    uses a non-standard name on your system.])])
 
-	AC_MSG_CHECKING([for pthread_yield])
-	pthread_yield_func=unknown
-        AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
-                        static void routine(void *a) { a = 0; }
-                        static void *start_routine(void *a) { return a; }],
-                       [pthread_t th; pthread_attr_t attr;
-                        pthread_yield();])],
-			[pthread_yield_func="pthread_yield";
-			AC_MSG_RESULT(yes)],
-			[AC_MSG_RESULT(no)])
-	if test "x$pthread_yield_func" = xunknown; then
-	   AC_MSG_CHECKING([for pthread_yeild_np])
-       	   AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
-                        static void routine(void *a) { a = 0; }
-                        static void *start_routine(void *a) { return a; }],
-                       [pthread_t th; pthread_attr_t attr;
-                        pthread_yield_np();])],
-			[pthread_yield_func="pthread_yield_np";
-			AC_MSG_RESULT(yes)],
-			[AC_MSG_RESULT(no)])
-	fi
-	if test "x$pthread_yield_func" = xunknown; then
-	   AC_MSG_ERROR([could not find pthread_yield function])
-	else
-		AC_DEFINE_UNQUOTED(PTHREAD_YIELD_FUNC, $pthread_yield_func,
-				   [Define to necessary func name if
-				   pthread_yield or pthread_yield_np do not
-				   exist on your system])
-	fi
-
         AC_CACHE_CHECK([if more special flags are required for pthreads],
             [ax_cv_PTHREAD_SPECIAL_FLAGS],
             [ax_cv_PTHREAD_SPECIAL_FLAGS=no