Update third_party/nss to NSS 3.15.4.

nss/lib/util/secdig.c

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "secdig.h"
 
 #include "secoid.h"
 #include "secasn1.h" 
 #include "secerr.h"
 
 /*
@@ skipping 11 matching lines @@
  * and encode).  I think that is all anybody ever wants to do anyway.
  */
 
 SECItem *
 SGN_EncodeDigestInfo(PLArenaPool *poolp, SECItem *dest, SGNDigestInfo *diginfo)
 {
     return SEC_ASN1EncodeItem (poolp, dest, diginfo, sgn_DigestInfoTemplate);
 }
 
 SGNDigestInfo *
-SGN_CreateDigestInfo(SECOidTag algorithm, unsigned char *sig, unsigned len)
+SGN_CreateDigestInfo(SECOidTag algorithm, const unsigned char *sig,
+                     unsigned len)
 {
     SGNDigestInfo *di;
     SECStatus rv;
     PLArenaPool *arena;
     SECItem *null_param;
     SECItem dummy_value;
 
     switch (algorithm) {
       case SEC_OID_MD2:
       case SEC_OID_MD5:
@@ skipping 128 matching lines @@
     SECComparison rv;
 
     /* Check signature algorithm's */
     rv = SECOID_CompareAlgorithmID(&a->digestAlgorithm, &b->digestAlgorithm);
     if (rv) return rv;
 
     /* Compare signature block length's */
     rv = SECITEM_CompareItem(&a->digest, &b->digest);
     return rv;
 }