[Bug c/111526] inconsistent handling of declaration after label

[P at draigBrady dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111526

--- Comment #4 from Pádraig Brady <P at draigBrady dot com> ---
Interestingly, gcc 13 _does_ warn with -Wc11-c2x-compat,
but does not warn with -Wpedantic