diff --git a/oggvorbis_artsplugin/oggPlayObject_impl.h b/oggvorbis_artsplugin/oggPlayObject_impl.h
index 2f1b0c0c..16a4ae24 100644
--- a/oggvorbis_artsplugin/oggPlayObject_impl.h
+++ b/oggvorbis_artsplugin/oggPlayObject_impl.h
@@ -1,7 +1,7 @@
 #ifndef OGGPLAYER_IMPL_H
 #define OGGPLAYER_IMPL_H "$Id$"
 
-#if defined(__GNU_LIBRARY__) && !defined(_SEM_SEMUN_UNDEFINED) || defined(__DragonFly__)
+#if defined(__GNU_LIBRARY__) && !defined(_SEM_SEMUN_UNDEFINED) || defined(__DragonFly__) || defined(__OpenBSD__)
 /* union semun is defined by including <sys/sem.h> */
 #else
 /* according to X/OPEN we have to define it ourselves */