fix: rewrite dylib install name on macOS so rpath resolution works

The ACINQ secp256k1-kmp-jni dylib ships with a relative LC_ID_DYLIB
("build/darwin/libsecp256k1-jni.dylib"). macOS dyld resolves this
literally, ignoring the -Wl,-rpath passed at link time, causing an
immediate abort at launch. Using install_name_tool to rewrite the
install name to @rpath/libsecp256k1-jni.dylib lets dyld find the
library via the rpath we already set.

https://claude.ai/code/session_01WSNE6QKiYM2ZutQD2UihCW

quartz/benchmarks/run_all.sh

@@ -60,6 +60,14 @@ if [ -z "$SO_FILE" ]; then
 fi
 cp "$SO_FILE" "$WORK/"
 
+# On macOS the dylib's LC_ID_DYLIB (install name) is a relative path like
+# "build/darwin/libsecp256k1-jni.dylib".  dyld resolves it literally, ignoring
+# -rpath, so the binary fails at launch.  Rewrite the install name to use
+# @rpath so the -Wl,-rpath we pass to gcc actually works.
+if [ "$OS_NAME" = "Darwin" ]; then
+    install_name_tool -id "@rpath/$SO_NAME" "$WORK/$SO_NAME" 2>/dev/null || true
+fi
+
 if ! gcc -O2 -o "$WORK/bench" "$BENCH_DIR/secp256k1_native_bench.c" \
     -L"$WORK" -lsecp256k1-jni -Wl,-rpath,"$WORK" 2>&1; then
     echo "gcc compilation failed"