posix_spawn_file_actions_addclose(3) on macOS
The text d53a42cb87b8, as macOS 10.14.6, macOS 10.14.3, macOS 10.14.2, macOS 10.14.1, macOS 10.13.6, macOS 10.13.5, macOS 10.13.4, macOS 10.13.3, macOS 10.13.2, macOS 10.13.1, macOS 10.13, macOS 10.12.6, macOS 10.12.5, macOS 10.12.4, macOS 10.12.3, macOS 10.12.2, macOS 10.12.1, macOS 10.12, OS X 10.11.6, OS X 10.11.5, OS X 10.11.4, OS X 10.11.3, OS X 10.11.2, OS X 10.11.1, OS X 10.11, OS X 10.10.5, OS X 10.10.4, OS X 10.10.3, OS X 10.10.2, OS X 10.10.1, OS X 10.10, OS X 10.9.5, OS X 10.9.4, OS X 10.9.3, OS X 10.9.2, OS X 10.9.1, OS X 10.9, Mac OS X 10.8.5, Mac OS X 10.8.4, Mac OS X 10.8.3, Mac OS X 10.8.2, Mac OS X 10.8.1, Mac OS X 10.8, Mac OS X 10.7.5, Mac OS X 10.7.4, Mac OS X 10.7.3, Mac OS X 10.7.2, Mac OS X 10.7.1, Mac OS X 10.7 shipped it.
add open or close actions to a posix_spawn_file_actions_t