`FileManager.enumerator(at*:)` doesn't work on WASI

[kkebo]

Motivation

FileManager.enumerator(at:) and FileManager.enumerator(atPath:) doesn't work on WASI since their underlying NSURLDirectoryEnumerator is just a stub on WASI.

The reason why it was a stub was that NSURLDirectoryEnumerator heavily used FTS and the wasi-libc didn't support it then.

https://github.com/apple/swift-corelibs-foundation/pull/4898/files#diff-dd2c49919954783c5266a5dce970eb43c41de6f017c12ad3474afd038f971c5fR1123

Proposed solution

FTS has been supported since wasi-libc 25, and swiftlang/swift main branch and release/6.3 branch are already using the greater version of wasi-libc than 25.

• https://github.com/swiftlang/swift/blob/0bb3177588380a81b39de0a156d912483f6222f0/utils/update_checkout/update-checkout-config.json#L193
• https://github.com/swiftlang/swift/blob/1597f2466310b9caf70c1ed235fd27e3c486551e/utils/update_checkout/update-checkout-config.json#L246

So we can use the proper NSURLDirectoryEnumerator on WASI as well.

Alternatives considered

No response

Additional information

I have already created PRs.

• [wasm] Enable NSURLDirectoryEnumerator on WASI #5418
• [6.3] [wasm] Enable NSURLDirectoryEnumerator on WASI #5419

[itingliu]

addressed in the two linked PRs

[kkebo]

FYI, #5418 has been replaced with #5422.