Make use of clock_gettime().

Index: src/xine-utils/memcpy.c
--- src/xine-utils/memcpy.c.orig
+++ src/xine-utils/memcpy.c
@@ -593,7 +593,7 @@ static const struct {
 
 static uint64_t memcpy_timing[sizeof(memcpy_method)/sizeof(memcpy_method[0])] = { 0, };
 
-#ifdef HAVE_POSIX_TIMERS
+#if defined(HAVE_POSIX_TIMERS) || defined(__OpenBSD__)
 /* Prefer clock_gettime() where available. */
 
 # ifndef CLOCK_THREAD_CPUTIME_ID
