Fix Sentry initialization on Amazon Linux

[tustanivsky]

Currently sentry-native is built using clang and libc++ to make the corresponding static libs included in sentry-unreal plugin compatible with UE. This introduces additional overhead for using Sentry on Linux since libc++ as one of the Crashpad dependencies has to be installed separately and for some distros this package is not available (i.e. AL 2/2023).

This PR suggests to build sentry-native in CI twice: once to obtain static libs using the current configuration and once to get the Crashpad executable not dependent on libc++ using gcc which then replaces binary obtained during the first build.

Related #431

Closes #635

[bitsandfoxes]

I think I'm still stuck on the problem conceptually: We can build sentry-native statically using clang & libc++. But the crashpad handler that gets build alongside it has the libc++ dependency?

[tustanivsky]

I think I'm still stuck on the problem conceptually: We can build sentry-native statically using clang & libc++. But the crashpad handler that gets build alongside it has the libc++ dependency?

@bitsandfoxes Yes, the crashpad_handler as it's currently built for Unreal has a dependency on libc++. To my understanding the existing sentry-native build scripts do not allow building crashpad executable separately with a configuration (compiler, standard library) that's different from the remaining SDK. So we came up with this "hack" when building things twice and combining the resulting artifacts allow us to avoid potential issues with additional deployment environment setup.

cc @supervacuus

[supervacuus]

I think I'm still stuck on the problem conceptually: We can build sentry-native statically using clang & libc++. But the crashpad handler that gets build alongside it has the libc++ dependency?

Everything you're building in this script has the libc++ dependency since you switched to clang, including libsentry.[a|so].

Building any library statically does not mean the libc++ dependency is gone; it is not linked statically to a standard library (and it is also unclear how much sense it would make in such a situation).

The difference is that this dependency is resolved for libsentry as part of the Unreal executable, whereas the crashpad_handler is a separate executable and gets the standard library the OS loader looks up for it.

[bitsandfoxes]

I would really like to see this covered by some smoke test. I.e. run that amazon docker image in CI?

[tustanivsky]

We should be able to add smoke tests once #658 is resolved.