diff --git a/src/stdafx.h b/src/stdafx.h
--- a/src/stdafx.h
+++ b/src/stdafx.h
@@ -360,6 +360,8 @@ CDECL error(const char *str, ...);
 #elif defined(OPENBSD)
 /* OpenBSD uses strcasecmp(3) */
 #define _stricmp strcasecmp
+/* OpenBSD furthermore already has an ALIGN macro. */
+#undef ALIGN
 #endif
 
 #if !defined(MORPHOS) && !defined(OPENBSD)