Whitelist UnexpectedException test for all architectures and recommend libunwind in INSTALL

[hmelder]

I am undecided about whether to add a try_compile to the CMakeLists.txt to automatically use CompilerRT and libunwind if they are available. This should exclude Windows and Android.

This PR should be merged after a fix for libgcc: _Unwind_RaiseException corrupts return value is implemented in GCC.

[hmelder]

On the other hand, automatic configuration is better than manually setting compile flags.

[hmelder]

What do you think @davidchisnall?

[davidchisnall]

I think this is the right thing (implicitly linking a non-default unwinded will break things for people), but I’d like CI to be green…

[hmelder]

but I’d like CI to be green…

We can use CompilerRT + libunwind in the CI

[hmelder]

I guess finding prebuild libunwind cross builds for ubuntu might be a bit difficult

[hmelder]

Seems like the GCC patch has not arrived in 24.04LTS :/