diff --git a/external/cddl/osnet/dist/tools/ctf/cvt/ctfmerge.c b/external/cddl/osnet/dist/tools/ctf/cvt/ctfmerge.c
index 23e5f3f77cb7..33ea618859e6 100644
--- a/external/cddl/osnet/dist/tools/ctf/cvt/ctfmerge.c
+++ b/external/cddl/osnet/dist/tools/ctf/cvt/ctfmerge.c
@@ -682,7 +682,7 @@ terminate_cleanup(void)
 	if (outfile == NULL)
 		return;
 
-#if !defined (__FreeBSD__) && !defined(__NetBSD__)
+#if !defined (__FreeBSD__) && !(defined(__NetBSD__) || HAVE_NBTOOL_CONFIG_H)
 	if (dounlink) {
 		fprintf(stderr, "Removing %s\n", outfile);
 		unlink(outfile);