[Bug fortran/93309] Wrong error about duplicate implicit none

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93309

--- Comment #6 from Tobias Burnus <burnus at gcc dot gnu.org> ---
(In reply to ripero84 from comment #4)
> Thank you!  Would it be possible to backport this fix to the other active
> branches?

Done so for GCC 9  – I did not check GCC 8 and I also do not think that it
belongs there.