FS-4695 fix apple build, seems there's no pthread_setschedprio on Mac, not sure…

FS-4695 fix apple build, seems there's no pthread_setschedprio on Mac, not sure if windows has the same problem in apr/threadproc/unix/thread.c

libs/apr/threadproc/unix/thread.c

@@ -174,10 +174,12 @@ APR_DECLARE(apr_status_t) apr_thread_create(apr_thread_t **new,
     }
 
     if ((stat = pthread_create((*new)->td, temp, dummy_worker, (*new))) == 0) {
+#ifndef __APPLE__
 		if (attr->priority) {
 			pthread_t *thread = (*new)->td;
 			pthread_setschedprio(*thread, attr->priority);
 		}
+#endif
 
         return APR_SUCCESS;
     }

libs/sofia-sip/libsofia-sip-ua/su/su_pthread_port.c

@@ -268,8 +268,12 @@ int su_pthreaded_port_start(su_port_create_f *create,
 
   pthread_mutex_lock(arg.mutex);
   if (pthread_create(&tid, &attr, su_pthread_port_clone_main, &arg) == 0) {
-#ifndef WIN32
-	  /* this needs to be revisited when pthread for windows supports thread priority settings */
+
+#if defined (WIN32)
+    /* this needs to be revisited when pthread for Windows supports thread priority settings */
+#elif defined (__APPLE__)
+    /* no such function on Apple */
+#else
 	  pthread_setschedprio(tid, 99);
 #endif
     pthread_cond_wait(arg.cv, arg.mutex);