// We use NewFile+Close because it is portable
		// unlike syscall.Close, whose parameter type varies.
		os.NewFile(prev, "").Close() // ignore error
	}
	return nil
}

//go:linkname runtime_setCrashFD runtime.setCrashFD

// all ones), writeErr and related functions write to it in addition
// to standard error.
//
// Initialized to -1 in schedinit.
var crashFD atomic.Uintptr

//go:linkname setCrashFD
func setCrashFD(fd uintptr) uintptr {
	// Don't change the crash FD if a crash is already in progress.
	//
	// Unlike the case below, this is not required for correctness, but it