diff --git a/libasn1fix/asn1fix_class.c b/libasn1fix/asn1fix_class.c
index c541fd6..f617c31 100644
--- a/libasn1fix/asn1fix_class.c
+++ b/libasn1fix/asn1fix_class.c
@@ -30,6 +30,8 @@
 	asn1p_expr_t *result;
 	asn1p_ref_t tmpref;
 
+	(void)mod_r;	/* Unused argument */
+
 	assert(ref->comp_count > 1);
 
 	DEBUG("%s(%s) for line %d", __func__,