[Bug libfortran/94694] [10 Regression][libgfortran] libgfortran does not compile on bare-metal aarch64-none-elf (newlib)

["rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94694

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Richard Earnshaw from comment #5)
> (In reply to Richard Biener from comment #2)
...
> > Since Fortran isn't release critical the only P1-ish part is that fortran
> > build is enabled on aarch64-elf and thus we can resolve this by adding
> > aarch64-elf-*) to
> > 
> > # Disable Fortran for some systems.
> > case "${target}" in
> >   mmix-*-*)
> >     # See <http://gcc.gnu.org/ml/gcc-patches/2004-11/msg00572.html>.
> >     unsupported_languages="$unsupported_languages fortran"
> >     ;;
> >   bpf-*-*)
> >     unsupported_languages="$unsupported_languages fortran"
> >     ;;
> > esac
> > 
> > technically aarch64-elf isn't a primary architecture.
> 
> Well in that case it should *test* the run time for compatibility.  It
> shouldn't assume it's incompatible just because of the target triplet.
> 
> aarch64-elf is a secondary platform.  It should still build.

Sure, that makes it P1-ish.  But since fortran and thus its runtime
library are not part of the release criteria disabling it [by default]
is a valid fix for that.  Or one could read the criteria that
only --enable-languages=c,c++ is relevant for bootstrap.

Yeah, the criteria as written are probably not the best, but they are
what they are.