[Bug fortran/66605] -Wunused-parameter causes internal compiler error with gfortran 5.1.0

[manu at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66605

--- Comment #3 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
BTW, is the resulting warning actually correct?