FirstChanceHandler execute once

[stima]

For platfroms that support FirstChanceHandler (windows, linux) execute it only once.

For windows that mimics behaviour of sentry__crashpad_handler but avoid an issue with a possible race condition for multiple executions of sentry__crashpad_handler:

• event creation on for a path crashpad_state_t::event_path during crashpad_backend_flush_scope
• crashpad_state_t::event inside sentry__crashpad_handler

That would also remove necessety of having sentry__enter_signal_handler for linux, because crashpad has same logic inside SignalHandler::HandleOrReraiseSignal.

[supervacuus]

Thanks, @stima and @ayx-rsavchenko! The way we currently set up our handlers, this makes sense. I have a couple of other changes in the same territory and will look at how to integrate this best when I am working on those.

[stima]

@supervacuus Hey any updates on that?

[supervacuus]

@supervacuus Hey any updates on that?

Hi @stima, I am truly sorry for not responding for such a long time. Over the last months, the focus has been on supporting downstream SDKs with various native topics that weren't necessarily Native SDK-related. This led to open PRs and issues related to standalone usage being put on the back burner. I will focus on standalone usage this month.

[Swatinem]

lgtm

[supervacuus]

Closing in favor of #109 and getsentry/sentry-native#1019 which integrated the general idea of the PR. Thanks!