fixup #290

tests/der_test.c

@@ -239,8 +239,8 @@ SEQUENCE(3 elem)
 static void _der_tests_print_flexi(ltc_asn1_list* l, unsigned int level)
 {
   char buf[1024];
-  char* name = NULL;
-  char* text = NULL;
+  const char* name = NULL;
+  const char* text = NULL;
   ltc_asn1_list* ostring = NULL;
   unsigned int n;