portability

diff --git a/skeletons/tests/check-length.c b/skeletons/tests/check-length.c
index d0edde3..7746bcf 100644
--- a/skeletons/tests/check-length.c
+++ b/skeletons/tests/check-length.c
@@ -58,7 +58,7 @@
 	assert(erval.encoded == buf_off);
 	assert(buf_off > size);
 
-	rval = ber_decode(&asn1_DEF_OCTET_STRING, &nos, buf, buf_off);
+	rval = ber_decode(&asn1_DEF_OCTET_STRING, (void **)&nos, buf, buf_off);
 	assert(rval.code == RC_OK);
 	assert(rval.consumed == buf_off);