macOS linker warnings in macOS ventura

Turns out ld shipped with Xcode 14+ emits a warning when using -undefined dynamic_lookup.`

ld: warning: -undefined dynamic_lookup may not work with chained fixups

Some investigation reveals that in fact -undefined dynamic_lookup doesn't work when:

• Link a shared library with the option
• Link it with a program that uses the chained-fixup introduced from macOS 12 and iOS 15

This is because -undefined dynamic_lookup uses lazy-bindings and they won't be bound while dyld fixes-up by traversing chained-fixup info.

However, we build extension modules with as bundles (-bundle) and they are loaded only through
dlopen, so it's safe to use -undefined dynamic_lookup in theory. So the warning produced by ld64 is
likely to be a false-positive.

ld64 also provides the -bundle_loader <executable> option, which allows resolving symbols defined in the executable symbol table while linking. It behaves almost the same with -undefined dynamic_lookup, but it makes the following changes:

• Require that unresolved symbols among input objects must be defined in the executable.
• Lazy symbol binding will lookup only the symbol table of the bundle loader executable. (-undefined dynamic_lookup lookups all symbol tables as flat namespace)

See "New Features" subsection under "Linking" section for chained fixup
developer.apple.com/documentation/xcode-release-notes/xcode-13-release-notes for more information.

Also, check the same problem in ruby where most of this information is taken from.

ファイル、テスト、エントリポイントは指定されていません。まず、macOS の拡張モジュールに関する CPython のリンカー設定と、-undefined dynamic_lookup の使用箇所を見つけます。現在の動作を ld64 の -bundle_loader オプションと比較します。Ventura/Xcode 14+ の警告に対処し、拡張モジュールの読み込みを壊していない状態になれば完了です。