For targets where SEH exceptions are used by default (on MinGW, only x86_64 so far), -munwind-tables are added automatically. If
-fseh-exeptions is enabled on a target where SEH exeptions are availble but not enabled by default yet (aarch64), we need to pass -munwind-tables if -fseh-exceptions was specified.
Once things have settled and this works fine in practice, the default can be switched from dwarf to SEH. Or is this unnecessary churn and we should just keep off this until the default can be changed?