Warning fixes from Christos Zoulas

- shadowed variables
- signed/unsigned confusion
- const lossage
- incomplete structure initializations
- unused code

lib/asn1/der_length.c

@@ -86,7 +86,7 @@ static size_t
 len_oid (const heim_oid *oid)
 {
     size_t ret = 1;
-    int n;
+    size_t n;
 
     for (n = 2; n < oid->length; ++n) {
 	unsigned u = oid->components[n];