[Bug fortran/55534] -Wno-missing-include-dirs does not work with gfortran

[manu at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55534

--- Comment #8 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
(In reply to Manuel López-Ibáñez from comment #7)
> The ideal fix for this would adding a function like:

I forgot about this bug and redid the above from scratch. But this time, I
actually tested that it works:
https://gcc.gnu.org/ml/fortran/2014-10/msg00019.html