SHM Segment cleanup upon SIGINT (and any other signal)

[yellowhatter]

Describe the bug

There is a problem around Ctrl-C's SIGINT handling. By default, process terminates upon SIGINT reception without properly executing any cleanups etc - and there is a problem, because we need to properly deref our SHM segments.

Since previous time we had SHM cleanup problem, we switched to a static-helper crate static_init with guaranteed cleanup on exit() call, but that didn't work for SIGINT :(

The solution can be to register signal handlers to perform cleanup, but this is incorrect, since it can interfere with user's signals as signal() API supports only one signal handler to be in place.

To be honest, I think we need to develop some more comprehensive segment cleanup mechanism to cover both SIGINT and SIGTERM cases.To be investigted

To reproduce

It can be reproduced by running any of our SHM examples

System info

Linux
Potentially Windows