* gostdsa-vko.c (gostdsa_vko): Use ecc_mod_mul_canonical to
compute the scalar used for ecc multiplication.

* eddsa-hash.c (_eddsa_hash): Ensure result is canonically
reduced. Two of the three call sites need that.

* ecc-gostdsa-verify.c (ecc_gostdsa_verify): Use ecc_mod_mul_canonical
to compute the scalars used for ecc multiplication.

* ecc-ecdsa-sign.c (ecc_ecdsa_sign): Ensure s output is reduced to
canonical range.

* ecc-ecdsa-verify.c (ecc_ecdsa_verify): Use ecc_mod_mul_canonical
to compute the scalars used for ecc multiplication.
* testsuite/ecdsa-verify-test.c (test_main): Add test case that
triggers an assert on 64-bit platforms, without above fix.
* testsuite/ecdsa-sign-test.c (test_main): Test case generating
the same signature.

* eddsa-verify.c (equal_h): Use ecc_mod_mul_canonical.

* ecc-mod-arith.c (ecc_mod_mul_canonical, ecc_mod_sqr_canonical):
New functions.
* ecc-internal.h: Declare and document new functions.
* curve448-eh-to-x.c (curve448_eh_to_x): Use ecc_mod_sqr_canonical.
* curve25519-eh-to-x.c (curve25519_eh_to_x): Use ecc_mod_mul_canonical.
* ecc-eh-to-a.c (ecc_eh_to_a): Likewise.
* ecc-j-to-a.c (ecc_j_to_a): Likewise.
* ecc-mul-m.c (ecc_mul_m): Likewise.

* configure.ac: Bump package version, to 3.7.1.
(LIBNETTLE_MINOR): Bump minor number, to 8.2.
(LIBHOGWEED_MINOR): Bump minor number, to 6.2.

* fat-ppc.c: Don't use __GLIBC_PREREQ in the same preprocessor
conditional as defined(__GLIBC_PREREQ), but move to a nested #if
conditional. Fixes compile error on OpenBSD/powerpc64, reported by
Jasper Lievisse Adriaanse.

* configure.ac: Bump package version, to 3.7.
(LIBNETTLE_MINOR): Bump minor number, to 8.1.
(LIBHOGWEED_MINOR): Bump minor number, to 6.1.

* powerpc64/p7/chacha-4core.asm (QR): Instruction level
interleaving in the main loop, written by Torbjörn Granlund.

* chacha-crypt.c: (_nettle_chacha_crypt_4core)
(_nettle_chacha_crypt32_4core): New functions.
* chacha-internal.h: Add prototypes for _nettle_chacha_4core and
related functions.
* configure.ac (asm_nettle_optional_list): Add chacha-4core.asm.
* powerpc64/fat/chacha-4core.asm: New file.
* powerpc64/p7/chacha-4core.asm: New file.
* fat-ppc.c (fat_init): When altivec is available, use
_nettle_chacha_crypt_4core and _nettle_chacha_crypt32_4core
instead of _2core variants.