This makes exception handling a lot simpler, since we don't have to convert any exceptions this way. Is also properly handles all the user-thrown exceptions.
Reviewed By: ldionne, #libc
Spies: arichardson, mstorsjo, libcxx-commits
Differential Revision: https://reviews.llvm.org/D154238
Those were found while trying to enable configurations like no-threads
and no-localization with Clang modules enabled.
Differential Revision: https://reviews.llvm.org/D153977