Merge bitcoin/bitcoin#21573: Update libsecp256k1 subtree to latest master

5c7ee1b2da6bf783d27034fca9dfd3a64ed525cb libsecp256k1 no longer has --with-bignum= configure option (Pieter Wuille)
bdca9bcb6c9379707d09c63f02326884befbefb2 Squashed 'src/secp256k1/' changes from 3967d96bf1..efad3506a8 (Pieter Wuille)
cabb5661234f8d832dbc3b65bf80b0acc02db0a0 Disable certain false positive warnings for libsecp256k1 msvc build (Pieter Wuille)

Pull request description:

  This updates our src/secp256k1 subtree to the latest upstream master. The changes include:

  * The introduction of safegcd-based modular inverses, reducing ECDSA signing time by 25%-30% and ECDSA verification time by 15%-17%.
    * [Original paper](https://gcd.cr.yp.to/papers.html) by Daniel J. Bernstein and Bo-Yin Yang
    * [Implementation](https://github.com/bitcoin-core/secp256k1/pull/767) by Peter Dettman; [final](https://github.com/bitcoin-core/secp256k1/pull/831) version
    * [Explanation](https://github.com/bitcoin-core/secp256k1/blob/master/doc/safegcd_implementation.md) of the algorithm using Python snippets
    * [Analysis](https://github.com/sipa/safegcd-bounds) of the maximum number of iterations the algorithm needs
    * [Formal proof in Coq](https://medium.com/blockstream/a-formal-proof-of-safegcd-bounds-695e1735a348) by Russell O'Connor, for a high-level equivalent algorithm
  * Removal of libgmp as an (optional) dependency (which wasn't used in the Bitcoin Core build)
  * CI changes (Travis -> Cirrus)
  * Build system improvements

ACKs for top commit:
  laanwj:
    Tested ACK 5c7ee1b2da6bf783d27034fca9dfd3a64ed525cb

Tree-SHA512: ad8ac3746264d279556a4aa7efdde3733e114fdba8856dd53218588521f04d83950366f5c1ea8fd56329b4c7fe08eedf8e206f8f26dbe3f0f81852e138655431

1 files changed, 198 insertions, 0 deletions

diff --git a/src/secp256k1/.cirrus.yml b/src/secp256k1/.cirrus.yml
new file mode 100644
index 0000000000..506a860336
--- /dev/null
+++ b/src/secp256k1/.cirrus.yml
@@ -0,0 +1,198 @@
+env:
+  WIDEMUL: auto
+  STATICPRECOMPUTATION: yes
+  ECMULTGENPRECISION: auto
+  ASM: no
+  BUILD: check
+  WITH_VALGRIND: yes
+  RUN_VALGRIND: no
+  EXTRAFLAGS:
+  HOST:
+  ECDH: no
+  RECOVERY: no
+  SCHNORRSIG: no
+  EXPERIMENTAL: no
+  CTIMETEST: yes
+  BENCH: yes
+  ITERS: 2
+  MAKEFLAGS: -j2
+
+cat_logs_snippet: &CAT_LOGS
+  always:
+    cat_tests_log_script:
+      - cat tests.log || true
+    cat_exhaustive_tests_log_script:
+      - cat exhaustive_tests.log || true
+    cat_valgrind_ctime_test_log_script:
+      - cat valgrind_ctime_test.log || true
+    cat_bench_log_script:
+      - cat bench.log || true
+  on_failure:
+    cat_config_log_script:
+      - cat config.log || true
+    cat_test_env_script:
+      - cat test_env.log || true
+    cat_ci_env_script:
+      - env
+
+merge_base_script_snippet: &MERGE_BASE
+  merge_base_script:
+    - if [ "$CIRRUS_PR" = "" ]; then exit 0; fi
+    - git fetch $CIRRUS_REPO_CLONE_URL $CIRRUS_BASE_BRANCH
+    - git config --global user.email "ci@ci.ci"
+    - git config --global user.name "ci"
+    - git merge FETCH_HEAD  # Merge base to detect silent merge conflicts
+
+task:
+  name: "x86_64: Linux (Debian stable)"
+  container:
+    dockerfile: ci/linux-debian.Dockerfile
+    # Reduce number of CPUs to be able to do more builds in parallel.
+    cpu: 1
+    # More than enough for our scripts.
+    memory: 1G
+  matrix: &ENV_MATRIX
+    - env: {WIDEMUL:  int64,  RECOVERY: yes}
+    - env: {WIDEMUL:  int64,                 ECDH: yes, EXPERIMENTAL: yes, SCHNORRSIG: yes}
+    - env: {WIDEMUL: int128}
+    - env: {WIDEMUL: int128,  RECOVERY: yes,            EXPERIMENTAL: yes, SCHNORRSIG: yes}
+    - env: {WIDEMUL: int128,                 ECDH: yes, EXPERIMENTAL: yes, SCHNORRSIG: yes}
+    - env: {WIDEMUL: int128,  ASM: x86_64}
+    - env: {                  RECOVERY: yes,            EXPERIMENTAL: yes, SCHNORRSIG: yes}
+    - env: {                  STATICPRECOMPUTATION: no}
+    - env: {BUILD: distcheck, WITH_VALGRIND: no, CTIMETEST: no, BENCH: no}
+    - env: {CPPFLAGS: -DDETERMINISTIC}
+    - env: {CFLAGS: -O0, CTIMETEST: no}
+    - env:
+        CFLAGS:  "-fsanitize=undefined -fno-omit-frame-pointer"
+        LDFLAGS: "-fsanitize=undefined -fno-omit-frame-pointer"
+        UBSAN_OPTIONS: "print_stacktrace=1:halt_on_error=1"
+        ASM: x86_64
+        ECDH: yes
+        RECOVERY: yes
+        EXPERIMENTAL: yes
+        SCHNORRSIG: yes
+        CTIMETEST: no
+    - env: { ECMULTGENPRECISION: 2 }
+    - env: { ECMULTGENPRECISION: 8 }
+    - env:
+        RUN_VALGRIND: yes
+        ASM: x86_64
+        ECDH: yes
+        RECOVERY: yes
+        EXPERIMENTAL: yes
+        SCHNORRSIG: yes
+        EXTRAFLAGS: "--disable-openssl-tests"
+        BUILD:
+  matrix:
+    - env:
+        CC: gcc
+    - env:
+        CC: clang
+  << : *MERGE_BASE
+  test_script:
+    - ./ci/cirrus.sh
+  << : *CAT_LOGS
+
+task:
+  name: "i686: Linux (Debian stable)"
+  container:
+    dockerfile: ci/linux-debian.Dockerfile
+    cpu: 1
+    memory: 1G
+  env:
+    HOST: i686-linux-gnu
+    ECDH: yes
+    RECOVERY: yes
+    EXPERIMENTAL: yes
+    SCHNORRSIG: yes
+  matrix:
+    - env:
+        CC: i686-linux-gnu-gcc
+    - env:
+        CC: clang --target=i686-pc-linux-gnu -isystem /usr/i686-linux-gnu/include
+  test_script:
+    - ./ci/cirrus.sh
+  << : *CAT_LOGS
+
+task:
+  name: "x86_64: macOS Catalina"
+  macos_instance:
+    image: catalina-base
+  env:
+    HOMEBREW_NO_AUTO_UPDATE: 1
+    HOMEBREW_NO_INSTALL_CLEANUP: 1
+    # Cirrus gives us a fixed number of 12 virtual CPUs. Not that we even have that many jobs at the moment...
+    MAKEFLAGS: -j13
+  matrix:
+    << : *ENV_MATRIX
+  matrix:
+    - env:
+        CC: gcc-9
+    - env:
+        CC: clang
+  # Update Command Line Tools
+  # Uncomment this if the Command Line Tools on the CirrusCI macOS image are too old to brew valgrind.
+  # See https://apple.stackexchange.com/a/195963 for the implementation.
+  ## update_clt_script:
+  ##   - system_profiler SPSoftwareDataType
+  ##   - touch /tmp/.com.apple.dt.CommandLineTools.installondemand.in-progress
+  ##   - |-
+  ##     PROD=$(softwareupdate -l | grep "*.*Command Line" | tail -n 1 | awk -F"*" '{print $2}' | sed -e 's/^ *//' | sed 's/Label: //g' | tr -d '\n')
+  ##   # For debugging
+  ##   - softwareupdate -l && echo "PROD: $PROD"
+  ##   - softwareupdate -i "$PROD" --verbose
+  ##   - rm /tmp/.com.apple.dt.CommandLineTools.installondemand.in-progress
+  ##
+  brew_valgrind_pre_script:
+    - brew config
+    - brew tap --shallow LouisBrunner/valgrind
+    # Fetch valgrind source but don't build it yet.
+    - brew fetch --HEAD LouisBrunner/valgrind/valgrind
+  brew_valgrind_cache:
+    # This is $(brew --cellar valgrind) but command substition does not work here.
+    folder: /usr/local/Cellar/valgrind
+    # Rebuild cache if ...
+    fingerprint_script:
+      # ... macOS version changes:
+      - sw_vers
+      # ... brew changes:
+      - brew config
+      # ... valgrind changes:
+      - git -C "$(brew --cache)/valgrind--git" rev-parse HEAD
+    populate_script:
+      # If there's no hit in the cache, build and install valgrind.
+      - brew install --HEAD LouisBrunner/valgrind/valgrind
+  brew_valgrind_post_script:
+    # If we have restored valgrind from the cache, tell brew to create symlink to the PATH.
+    # If we haven't restored from cached (and just run brew install), this is a no-op.
+    - brew link valgrind
+  brew_script:
+    - brew install automake libtool gcc@9
+  << : *MERGE_BASE
+  test_script:
+    - ./ci/cirrus.sh
+  << : *CAT_LOGS
+
+task:
+  name: "s390x (big-endian): Linux (Debian stable, QEMU)"
+  container:
+    dockerfile: ci/linux-debian.Dockerfile
+    cpu: 1
+    memory: 1G
+  env:
+    QEMU_CMD: qemu-s390x
+    HOST: s390x-linux-gnu
+    BUILD:
+    WITH_VALGRIND: no
+    ECDH: yes
+    RECOVERY: yes
+    EXPERIMENTAL: yes
+    SCHNORRSIG: yes
+    CTIMETEST: no
+  << : *MERGE_BASE
+  test_script:
+    # https://sourceware.org/bugzilla/show_bug.cgi?id=27008
+    - rm /etc/ld.so.cache
+    - ./ci/cirrus.sh
+  << : *CAT_LOGS