[Bug c/92487] case label error when label is made from character of C string

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92487

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
>So this is some GNU extension, but why GCC doesn't support it?

Because it was undocumented one which was removed a long time ago.