dispatch_once(3) on macOS
The text d698aa470f76, as macOS 14.3, macOS 14.2, macOS 14.1, macOS 14.0, macOS 13.5, macOS 13.4, macOS 13.3, macOS 13.2, macOS 13.1, macOS 13.0, macOS 12.5, macOS 12.4, macOS 12.3, macOS 12.2, macOS 12.1, macOS 12.0.1, macOS 11.5, macOS 11.4, macOS 11.3, macOS 11.2, macOS 11.1, macOS 11.0.1 shipped it.
execute a block only once