Index: btest.c
--- btest.c.orig
+++ btest.c
@@ -646,7 +646,7 @@ void *test_udp_tx(void *arg) {
 		//timespec_dump("sleep until: ", &nextPacketTime);
 		clock_gettime(CLOCK_MONOTONIC, &now);
 		if (now.tv_sec <= nextPacketTime.tv_sec && now.tv_nsec < nextPacketTime.tv_nsec) {
-#ifdef __MACH__
+#if defined(__MACH__) || defined(__OpenBSD__)
 			clock_nanosleep_abstime(&nextPacketTime);
 #else
 			if (clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &nextPacketTime, NULL) < 0) {
