upstream: update the Streamlined NTRU Prime code from the "ref"

implementation in SUPERCOP 20201130 to the "compact" implementation in
SUPERCOP 20240808. The new version is substantially faster. Thanks to Daniel
J Bernstein for pointing out the new implementation (and of course for
writing it).

tested in snaps/ok deraadt@

OpenBSD-Commit-ID: bf1a77924c125ecdbf03e2f3df8ad13bd3dafdcb

kexsntrup761x25519.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: kexsntrup761x25519.c,v 1.2 2021/12/05 12:28:27 jsg Exp $ */
+/* $OpenBSD: kexsntrup761x25519.c,v 1.3 2024/09/15 02:20:51 djm Exp $ */
 /*
  * Copyright (c) 2019 Markus Friedl.  All rights reserved.
  *
@@ -39,6 +39,10 @@
 #include "digest.h"
 #include "ssherr.h"
 
+volatile crypto_int16 crypto_int16_optblocker = 0;
+volatile crypto_int32 crypto_int32_optblocker = 0;
+volatile crypto_int64 crypto_int64_optblocker = 0;
+
 int
 kex_kem_sntrup761x25519_keypair(struct kex *kex)
 {