I'm not sure how long this has been happening, but I am unable to build with the public SDK in Xcode, getting "can't find additional SDK" warnings. I've traced this back to XCBuild refusing to load e.g. `WebKitLibraries/SDKs/iphonesimulator17.0-additions.sdk` when it has already loaded `WebKitLibraries/SDKs/macosx14.0-additions.sdk`, because they have the same identifier. I'm guessing that this can only happen in Xcode, because XCBuild runs as a long-lived daemon process, whereas in command-line builds it's one-shot and would only load the additions SDK for the selected platform.
<rdar://problem/121698895>
Committed 273594@main (0b964655403e): <https://commits.webkit.org/273594@main> Reviewed commits have been landed. Closing PR #23338 and removing active labels.