[Bug fortran/82995] Segmentation fault passing optional argument to intrinsic sum function

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82995

--- Comment #3 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
OK! I have overlooked the line

        logical, intent(in), optional :: mask(:) 

in my_sum and it rung some bell. This PR is related to/duplicate of pr67277.