Android cross-compilation errors

[therealjmj]

After successful building for months, we are hitting a new cross-compilation build error on multiple machines, while building leveldown-nodejs-mobile (and leveldown) as a native module across all Android architectures.

...
error: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool: file: Release/obj.target/leveldb/deps/leveldb/leveldb-1.20/util/options.o is not an object file (not allowed in a library)
error: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool: file: Release/obj.target/leveldb/deps/leveldb/leveldb-1.20/util/status.o is not an object file (not allowed in a library)
error: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool: file: Release/obj.target/leveldb/deps/leveldb/leveldb-1.20/port/port_posix.o is not an object file (not allowed in a library)
error: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool: file: Release/obj.target/leveldb/deps/leveldb/leveldb-1.20/util/env_posix.o is not an object file (not allowed in a library)
make: *** [Release/leveldb.a] Error 1

gyp ERR! build error 
gyp ERR! stack Error: `make` failed with exit code: 2
gyp ERR! stack     at ChildProcess.onExit (/Users/<HOME>/.nvm/versions/node/v16.15.1/lib/node_modules/node-gyp/lib/build.js:194:23)
gyp ERR! stack     at ChildProcess.emit (node:events:527:28)
gyp ERR! stack     at Process.ChildProcess._handle.onexit (node:internal/child_process:291:12)
gyp ERR! System Darwin 21.5.0
gyp ERR! command "/Users/<HOME>/.nvm/versions/node/v16.15.1/bin/node" "/Users/johnnym/.nvm/versions/node/v16.15.1/bin/node-gyp" "rebuild" "--build-from-source" "--verbose"
gyp ERR! cwd /Users/<PROJ>/android/build/nodejs-native-assets-temp-build/nodejs-native-assets-armeabi-v7a/nodejs-project/node_modules/leveldown
gyp ERR! node -v v16.15.1
gyp ERR! node-gyp -v v9.0.0

Wondering if anyone has seen this, or has any ideas for debugging?

[therealjmj]

The above "not an object file" errors follow a variety of these build warnings:

~/Library/Android/sdk/ndk/22.1.7171670/toolchains/llvm/prebuilt/darwin-x86_64/bin/armv7a-linux-androideabi24-clang++ -o Release/obj.target/leveldb/deps/leveldb/leveldb-1.20/util/env_posix.o ../deps/leveldb/leveldb-1.20/util/env_posix.cc '-DNODE_GYP_MODULE_NAME=leveldb' '-DUSING_UV_SHARED=1' '-DUSING_V8_SHARED=1' '-DV8_DEPRECATION_WARNINGS=1' '-DV8_DEPRECATION_WARNINGS' '-DV8_IMMINENT_DEPRECATION_WARNINGS' '-D_LARGEFILE_SOURCE' '-D_FILE_OFFSET_BITS=64' '-D__STDC_FORMAT_MACROS' '-DOPENSSL_THREADS' '-DOPENSSL_NO_ASM' '-DSNAPPY=1' '-DLEVELDB_PLATFORM_POSIX=1' '-DOS_ANDROID=1' '-D_REENTRANT=1' '-D_GLIBCXX_USE_C99_MATH' -I/Users/johnnym/railway-private/node_modules/nodejs-mobile-react-native/android/libnode/include/node -I/Users/johnnym/railway-private/node_modules/nodejs-mobile-react-native/android/libnode/src -I/Users/johnnym/railway-private/node_modules/nodejs-mobile-react-native/android/libnode/deps/openssl/config -I/Users/johnnym/railway-private/node_modules/nodejs-mobile-react-native/android/libnode/deps/openssl/openssl/include -I/Users/johnnym/railway-private/node_modules/nodejs-mobile-react-native/android/libnode/deps/uv/include -I/Users/johnnym/railway-private/node_modules/nodejs-mobile-react-native/android/libnode/deps/zlib -I/Users/johnnym/railway-private/node_modules/nodejs-mobile-react-native/android/libnode/deps/v8/include -I../deps/leveldb/leveldb-1.20 -I../deps/leveldb/leveldb-1.20/include -I../deps/snappy/linux -I../deps/snappy/snappy  -fasm-blocks -mpascal-strings -O3 -gdwarf-2 -arch x86_64  -MMD -MF ./Release/.deps/Release/obj.target/leveldb/deps/leveldb/leveldb-1.20/util/env_posix.o.d.raw   -c
clang++: warning: argument unused during compilation: '-arch x86_64' [-Wunused-command-line-argument]