At least with GNAT, it isn't that bad - you don't have to port support for tasking when targeting an architecture or OS - e.g. there's it supports bare-metal on

At least with GNAT, it isn't that bad - you don't have to port support for tasking when targeting an architecture or OS - e.g. there's it supports bare-metal on many ARM boards, the runtime+glue needed is not much more than for a C compiler