- Phil Blundell added the CURLOPT_SCOPE option, as well as adjusted the URL

parser to allow numerical IPv6-addresses to be specified with the scope
  given, as per RFC4007 - with a percent letter that itself needs to be URL
  escaped. For example, for an address of fe80::1234%1 the HTTP URL is:
  "http://[fe80::1234%251]/"

include/curl/curl.h

@@ -1211,6 +1211,9 @@ typedef enum {
   /* Issuer certificate */
   CINIT(ISSUERCERT, OBJECTPOINT, 170),
 
+  /* (IPv6) Address scope */
+  CINIT(ADDRESS_SCOPE, LONG, 171),
+
   CURLOPT_LASTENTRY /* the last unused */
 } CURLoption;