Merge bitcoin/bitcoin#23383: Update libsecp256k1 subtree to current master

314195c8be3bd7db0d5817c4fb3aa85c84363ce9 Remove unnecessary cast in CKey::SignSchnorr (Pieter Wuille)
a1f76cdb22e3278a48d63dd23c1fe3308daedd8c Remove --disable-openssl-tests for libsecp256k1 configure (Pieter Wuille)
86dbc4d075decb82fbba837aaa283cf0561897ad Squashed 'src/secp256k1/' changes from be8d9c262f..0559fc6e41 (Pieter Wuille)

Pull request description:

  The motivation for this bump is getting rid of a cast in `CKey::SignSchnorr`; the `aux_rand` argument isn't modified by the `secp256k1_schnorrsig_sign` function, but was marked as non-`const` anyway. This is fixed now (bitcoin-core/secp256k1#966), and the cast is removed in this PR.

  There are a few other relevant changes:
  * (bitcoin-core/secp256k1#956): replaces a runtime-computed table with a precomputed one; this adds arouns 1 MiB to the binary size, but is a step towards significantly simplifying the API. If 1 MiB is too much, it can be reduced by 2 or 4 (or more) for a slight verification performance reduction.
  * (bitcoin-core/secp256k1#983): removes (test/bench only) OpenSSL support entirely, removing the need to pass `--disable-openssl-tests` (see #23314).
  * (bitcoin-core/secp256k1#810): mild performance increase for 64-bit non-x86 platforms.
  * (bitcoin-core/secp256k1#1002): Make aux_rnd32==NULL behave identical to 0x0000..00 (which impacts BIP341/BIP342 signing in Bitcoin Core, making it more strictly BIP340 compliant, though not in a manner that affects security).

ACKs for top commit:
  fanquake:
    ACK 314195c8be3bd7db0d5817c4fb3aa85c84363ce9 - this includes a nice simplification to the lilbsecp build system (and thus our build system), and fixes issues like #22854. Did a Guix build on x86 (above), as well as a build on arm64 (except for the arm64 host):

Tree-SHA512: 0e048390fc148fbbdf5b98d9cce8c71067564e7d69d97b68347808a9bc45a04f4fc653c392c880d79d5d8b9cf282195520955581ac4f1595f6a948080cf5949d

1 files changed, 7 insertions, 67 deletions

diff --git a/src/secp256k1/build-aux/m4/bitcoin_secp.m4 b/src/secp256k1/build-aux/m4/bitcoin_secp.m4
index 8245b2b863..c14d09fa1b 100644
--- a/src/secp256k1/build-aux/m4/bitcoin_secp.m4
+++ b/src/secp256k1/build-aux/m4/bitcoin_secp.m4
@@ -9,77 +9,17 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
 AC_MSG_RESULT([$has_64bit_asm])
 ])
 
-dnl
-AC_DEFUN([SECP_OPENSSL_CHECK],[
-  has_libcrypto=no
-  m4_ifdef([PKG_CHECK_MODULES],[
-    PKG_CHECK_MODULES([CRYPTO], [libcrypto], [has_libcrypto=yes],[has_libcrypto=no])
-    if test x"$has_libcrypto" = x"yes"; then
-      TEMP_LIBS="$LIBS"
-      LIBS="$LIBS $CRYPTO_LIBS"
-      AC_CHECK_LIB(crypto, main,[AC_DEFINE(HAVE_LIBCRYPTO,1,[Define this symbol if libcrypto is installed])],[has_libcrypto=no])
-      LIBS="$TEMP_LIBS"
-    fi
-  ])
-  if test x$has_libcrypto = xno; then
-    AC_CHECK_HEADER(openssl/crypto.h,[
-      AC_CHECK_LIB(crypto, main,[
-        has_libcrypto=yes
-        CRYPTO_LIBS=-lcrypto
-        AC_DEFINE(HAVE_LIBCRYPTO,1,[Define this symbol if libcrypto is installed])
-      ])
-    ])
-    LIBS=
-  fi
-if test x"$has_libcrypto" = x"yes" && test x"$has_openssl_ec" = x; then
-  AC_MSG_CHECKING(for EC functions in libcrypto)
-  CPPFLAGS_TEMP="$CPPFLAGS"
-  CPPFLAGS="$CRYPTO_CPPFLAGS $CPPFLAGS"
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-    #include <openssl/bn.h>
-    #include <openssl/ec.h>
-    #include <openssl/ecdsa.h>
-    #include <openssl/obj_mac.h>]],[[
-    # if OPENSSL_VERSION_NUMBER < 0x10100000L
-    void ECDSA_SIG_get0(const ECDSA_SIG *sig, const BIGNUM **pr, const BIGNUM **ps) {(void)sig->r; (void)sig->s;}
-    # endif
-
-    unsigned int zero = 0;
-    const unsigned char *zero_ptr = (unsigned char*)&zero;
-    EC_KEY_free(EC_KEY_new_by_curve_name(NID_secp256k1));
-    EC_KEY *eckey = EC_KEY_new();
-    EC_GROUP *group = EC_GROUP_new_by_curve_name(NID_secp256k1);
-    EC_KEY_set_group(eckey, group);
-    ECDSA_sign(0, NULL, 0, NULL, &zero, eckey);
-    ECDSA_verify(0, NULL, 0, NULL, 0, eckey);
-    o2i_ECPublicKey(&eckey, &zero_ptr, 0);
-    d2i_ECPrivateKey(&eckey, &zero_ptr, 0);
-    EC_KEY_check_key(eckey);
-    EC_KEY_free(eckey);
-    EC_GROUP_free(group);
-    ECDSA_SIG *sig_openssl;
-    sig_openssl = ECDSA_SIG_new();
-    d2i_ECDSA_SIG(&sig_openssl, &zero_ptr, 0);
-    i2d_ECDSA_SIG(sig_openssl, NULL);
-    ECDSA_SIG_get0(sig_openssl, NULL, NULL);
-    ECDSA_SIG_free(sig_openssl);
-    const BIGNUM *bignum = BN_value_one();
-    BN_is_negative(bignum);
-    BN_num_bits(bignum);
-    if (sizeof(zero) >= BN_num_bytes(bignum)) {
-        BN_bn2bin(bignum, (unsigned char*)&zero);
-    }
-  ]])],[has_openssl_ec=yes],[has_openssl_ec=no])
-  AC_MSG_RESULT([$has_openssl_ec])
-  CPPFLAGS="$CPPFLAGS_TEMP"
-fi
-])
-
 AC_DEFUN([SECP_VALGRIND_CHECK],[
 if test x"$has_valgrind" != x"yes"; then
   CPPFLAGS_TEMP="$CPPFLAGS"
   CPPFLAGS="$VALGRIND_CPPFLAGS $CPPFLAGS"
-  AC_CHECK_HEADER([valgrind/memcheck.h], [has_valgrind=yes; AC_DEFINE(HAVE_VALGRIND,1,[Define this symbol if valgrind is installed])])
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+    #include <valgrind/memcheck.h>
+  ]], [[
+    #if defined(NVALGRIND)
+    #  error "Valgrind does not support this platform."
+    #endif
+  ]])], [has_valgrind=yes; AC_DEFINE(HAVE_VALGRIND,1,[Define this symbol if valgrind is installed, and it supports the host platform])])
 fi
 ])