Because the documentation says to rely on that.

Fixes #5022. Xcode overwrites this variable for UI tests. The build settings reference confirms that this is the variable to rely on.

[TargetInspector] Raise a friendly error when unable to determine

platform

Disallow shallow clones of specs repos

Refactor SourcesManager to use Source/MasterSource

Fix typos in CHANGELOG.md

[Bundle] Update RuboCop

[FileAccessor] Access root-only values from the spec consumer

[Analyzer] Unlock local dependencies only if their specification changes