add some INTEGER OER encoding code
diff --git a/skeletons/oer_support.h b/skeletons/oer_support.h
index 3fba47e..727d7db 100644
--- a/skeletons/oer_support.h
+++ b/skeletons/oer_support.h
@@ -38,6 +38,12 @@
*/
ssize_t oer_fetch_length(const void *bufptr, size_t size, size_t *len_r);
+/*
+ * Serialize OER length. Returns the number of bytes serialized
+ * or -1 if a given callback returned with negative result.
+ */
+ssize_t oer_serialize_length(size_t length, asn_app_consume_bytes_f *cb, void *app_key);
+
#ifdef __cplusplus
}