fix(build): derive the macOS Berkeley DB depends triple from the build arch

The macOS release path hardcoded aarch64-apple-darwin for the wallet-rebuild
helper's static libdb and — unlike the Linux/Windows paths — never passed
-DBDB_INCLUDE_DIR/-DBDB_LIBRARY to CMake. So on an Intel Mac the helper either
couldn't find libdb, or picked up macOS's SDK stub /usr/include/db.h (a DB 1.85
shim with no db_create) and failed to compile.

- mac_bdb_dir(): map the target arch to the depends triple (x86_64 ->
  x86_64-apple-darwin, arm64 -> aarch64-apple-darwin; universal / unknown falls
  back to the host arch).
- Pass -DBDB_INCLUDE_DIR / -DBDB_LIBRARY (when the vendored libdb is present) in
  BOTH the native and osxcross configures, so CMake uses our BDB 6.2 header
  instead of the SDK stub. Full-node only (lite has no BDB wallet.dat).
- Use the derived triple in require_wallet_rebuild_helper's fix hint.

Verified end-to-end by building both ObsidianDragon 2.0.1 and ObsidianDragonLite
1.1.0 .dmg/.app on an Intel Mac (x86_64; built single-arch via DRAGONX_MAC_ARCHS
since the vendored deps are x86_64-only).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

build.sh

@@ -213,6 +213,21 @@ require_wallet_rebuild_helper() {
     info "  wallet-rebuild helper present: $helper"
 }
 
+# Vendored Berkeley DB depends directory for the macOS wallet-rebuild helper, by TARGET arch. The daemon
+# links a static libdb-6.2; the helper must match the build arch, so derive the triple from it rather than
+# hardcoding one. Single-arch: x86_64 -> x86_64-apple-darwin, arm64 -> aarch64-apple-darwin. "universal"
+# (or anything unexpected) falls back to the host arch — a universal .app needs a universal libdb, so if
+# only a single-arch libdb is vendored, build single-arch via DRAGONX_MAC_ARCHS.
+mac_bdb_dir() {
+    local arch="$1" triple
+    case "$arch" in
+        x86_64) triple="x86_64-apple-darwin" ;;
+        arm64)  triple="aarch64-apple-darwin" ;;
+        *)      [[ "$(uname -m)" == "arm64" ]] && triple="aarch64-apple-darwin" || triple="x86_64-apple-darwin" ;;
+    esac
+    printf '%s/external/dragonx/depends/%s\n' "$SCRIPT_DIR" "$triple"
+}
+
 # ── Helper: find resource files ──────────────────────────────────────────────
 find_sapling_params() {
     local dirs=(
@@ -1083,6 +1098,12 @@ TOOLCHAIN
         fi
 
         info "Configuring (cross-compile via osxcross) ..."
+        # Vendored static libdb for the recovery helper (full-node only), by target arch; see mac_bdb_dir.
+        local mac_bdb; mac_bdb="$(mac_bdb_dir "$MAC_ARCH")"
+        local BDB_ARGS=()
+        if should_bundle_full_node_assets && [[ -f "$mac_bdb/lib/libdb-6.2.a" && -f "$mac_bdb/include/db.h" ]]; then
+            BDB_ARGS=( -DBDB_INCLUDE_DIR="$mac_bdb/include" -DBDB_LIBRARY="$mac_bdb/lib/libdb-6.2.a" )
+        fi
         cmake "$SCRIPT_DIR" \
             -DCMAKE_TOOLCHAIN_FILE="$bd/osxcross-toolchain.cmake" \
             -DCMAKE_BUILD_TYPE=Release \
@@ -1090,6 +1111,7 @@ TOOLCHAIN
             -DDRAGONX_USE_SYSTEM_SDL3=OFF \
             -DCMAKE_OSX_DEPLOYMENT_TARGET=11.0 \
             ${COMPILER_RT:+-DOSXCROSS_COMPILER_RT="$COMPILER_RT"} \
+            "${BDB_ARGS[@]}" \
             "${CMAKE_LITE_ARGS[@]}"
     else
         # Build libsodium as universal if needed
@@ -1111,12 +1133,19 @@ TOOLCHAIN
         fi
 
         info "Configuring (native macOS, arch: $MAC_ARCHS) ..."
+        # Point CMake at the vendored static libdb for the recovery helper (full-node only); see mac_bdb_dir.
+        local mac_bdb; mac_bdb="$(mac_bdb_dir "$MAC_ARCH")"
+        local BDB_ARGS=()
+        if should_bundle_full_node_assets && [[ -f "$mac_bdb/lib/libdb-6.2.a" && -f "$mac_bdb/include/db.h" ]]; then
+            BDB_ARGS=( -DBDB_INCLUDE_DIR="$mac_bdb/include" -DBDB_LIBRARY="$mac_bdb/lib/libdb-6.2.a" )
+        fi
         cmake "$SCRIPT_DIR" \
             -DCMAKE_BUILD_TYPE=Release \
             -DCMAKE_CXX_FLAGS_RELEASE="-O3 -DNDEBUG" \
             -DDRAGONX_USE_SYSTEM_SDL3=OFF \
             -DCMAKE_OSX_DEPLOYMENT_TARGET=11.0 \
             -DCMAKE_OSX_ARCHITECTURES="$MAC_ARCHS" \
+            "${BDB_ARGS[@]}" \
             "${CMAKE_LITE_ARGS[@]}"
     fi
 
@@ -1128,7 +1157,7 @@ TOOLCHAIN
     # A full-node release MUST include the recovery helper. macOS needs a static libdb-6.2 (Homebrew
     # berkeley-db for a native build, or a vendored external/dragonx/depends/<triple>) — otherwise CMake
     # skips the target and this fails loudly rather than shipping a mac release with no recovery option.
-    require_wallet_rebuild_helper "bin/dragonx-wallet-rebuild" "$SCRIPT_DIR/external/dragonx/depends/aarch64-apple-darwin"
+    require_wallet_rebuild_helper "bin/dragonx-wallet-rebuild" "$(mac_bdb_dir "$MAC_ARCH")"
 
     # Strip — use osxcross strip for cross-builds
     if $IS_CROSS; then