fatal-signal: Pass the signal number to the action.
* lib/fatal-signal.h (at_fatal_signal): Change the signature.
* lib/fatal-signal.c (action_t): Take the signal number as parameter.
(fatal_signal_handler): Pass the signal number to the action.
* lib/clean-temp.c (cleanup_action): Renamed from cleanup. Take the
signal number as parameter.
(create_temp_dir): Update.
* lib/wait-process.c (cleanup_slaves_action): New function.
(register_slave_subprocess): Update at_fatal_signal invocation.
* NEWS: Mention the change.