Function set_terminal_deadlock_hook 

pub fn set_terminal_deadlock_hook(hook: Option<TerminalDeadlockHook>)

Install (or, with None, remove) the hook a terminal deadlock report is handed to just before the process exits. The exit cannot return an error to a caller, so run --verify uses this to record the run as failed by a deadlock instead of leaving its pending no-result stamp.