[Bug fortran/88929] ICE on building MPICH 3.2 with GCC 9 with ISO_Fortran_binding

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88929

--- Comment #4 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
There is a partially reduced test in pr88908 (TODO reduce the modules).