Index: hdl.c
--- hdl.c.orig
+++ hdl.c
@@ -6,7 +6,7 @@
 #define _HDL_C_
 #define _HUTIL_DLL_
 
-#if !defined(WIN32) && !defined(__FreeBSD__) && !defined(__APPLE__)
+#if !defined(WIN32) && !defined(__FreeBSD__) && !defined(__APPLE__) && !defined(__OpenBSD__)
 #define ZZ_NO_BACKLINK
 #endif
 
