[RFC PATCH v4 3/5] support record failure: flush stdout, use _exit ()

[Florian Weimer]

* Mathieu Desnoyers:

> Using "exit ()" from pthread_atfork handlers hangs the process. It is
> therefore not a good way to exit when reporting a testing error.
>
> Use _exit () instead, which directly exits the process. However,
> considering that the buffered stdout is used to output test failure
> messages, we first need to flush stdout before exiting.

This is not correct; we need the atexit handlers for cleaning up
temporary files.

It should be possible to call support_record_failure and rely on the
shared memory segment to register the test failure, so that it is
eventually reflected in the exit state (even if the failure happens in
the subprocess).

Thanks,
Florian