[Bug c++/110848] Consider enabling -Wvla by default in C++ modes

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110848

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Maybe my issue is this has been a documented extension for 20 years now.
-pedantic or -std=c++NN has always rejected it like it should. GCC has other
extensions which folks could use by accident too (like statement expressions).
Why is VLA special here?