Fix division by zero bug triggered by pointers to opaque structs.

encoding2.c

@@ -113,6 +113,11 @@ static void parse_struct(const char **type, type_parser callback, void *context)
 
 inline static void round_up(size_t *v, size_t b)
 {
+        if (0 == b)
+	{
+		return;
+	}
+
 	if (*v % b)
 	{
 		*v += b - (*v % b);