[Bug c/105499] inconsistency between -Werror=c++-compat and g++ in __extension__ block

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105499

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
__extension__ is supposed to disable compatibility warnings since they are
written in GNU C. Just happens that you enabled compatibility warnings to C++
which are also disabled.

This is the misunderstanding of what the warning and what __extension__ does.