Fix signal handler

[elfring]

The function “exit” does not belong to the list of async-signal-safe functions.
I guess that a different program design will be needed for your function “DeadPipe‎”.

[ThomasAdam]

@elfring

I'm going to ask you one last time. Please can you stop opening issues with descriptions of code changes, and instead send through a PR for the code changes you're describing?

[elfring]

💭 I imagine that corresponding software design options need to be clarified before.

• sigwaitinfo()
• Self-pipe trick
• Signal-safe locks

[ThomasAdam]

No, not really. Just send through a patch you feel looks right, and we can discuss it.

[elfring]

How do you think about to concentrate signal handling in a corresponding thread? 🤔

[ThomasAdam]

For the love of god, @elfring send a patch through. Stop asking all these crappy ephemeral questions.

This is your last warning. After this, I've a mind to block you.