[Bug c/113776] [14 regression] postgresql-16.1 build failure with -Werror=vla in configure test

[sjames at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113776

--- Comment #1 from Sam James <sjames at gcc dot gnu.org> ---
tl;dr: are d and f supposed to be compilable / are they constant expressions in
C?