perf(mobile): sign iOS events with native secp256k1

Signed-off-by: Tom Brow <tomb@block.xyz>

scripts/test-mobile-native-signing.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+# Exercise the production C adapter from Dart on the macOS native CI runner.
+set -euo pipefail
+cd "$(dirname "$0")/.."
+. ./bin/activate-hermit
+native_test_dir=$(mktemp -d)
+trap 'rm -rf "$native_test_dir"' EXIT
+source_dir=mobile/ios/BuzzPushKit/Sources/CSecp256k1
+clang -O2 -dynamiclib -DENABLE_MODULE_EXTRAKEYS -DENABLE_MODULE_SCHNORRSIG \
+  -framework Security \
+  "$source_dir/buzz_signer.c" \
+  "$source_dir/vendor/src/secp256k1.c" \
+  "$source_dir/vendor/src/precomputed_ecmult.c" \
+  "$source_dir/vendor/src/precomputed_ecmult_gen.c" \
+  -o "$native_test_dir/libbuzz_signer.dylib"
+cd mobile
+BUZZ_SIGNER_LIBRARY="$native_test_dir/libbuzz_signer.dylib" \
+  flutter test test/shared/crypto/event_signer_test.dart