Remove runtime dependency on libstdc++

[jkotas]

CoreRT runtime does not use any C++ features (exception handling, etc.), but it still depends on libstdc++ here and there for no good reason. Consider cleaning these up and remote dependency on libstdc++ to improve minimal footprint.

[janvorli]

@jkotas CoreRT uses new / delete operators and these are implemented in the libstdc++. It also uses std::terminate. And the System.Globalization.Native uses std::string.

I have looked at the Exceptions simple test to find the symbols using objdump -x Exceptions | grep GLIBCXX | c++filt

[jkotas]

CoreRT uses new / delete operators and these are implemented in the libstdc++.

Yes, these are the kind of dependencies that I meant. E.g. we can have our own trivial local impl instead of pulling in the libstdc++ dependency.

System.Globalization.Native uses std::string

I am not worried about System.Globalization.Native as much. If you link with System.Globalization.Native, you are pulling in the large libicu dependency (order of magnitude more than libstdc++) and so the extra libc++ does not matter. I think this is really only interesting with the InvariantGlobalization-only config that does not have the libicu dependency: micro-service, running on vanilla Alpine, ... .