[Bug c++/65547] Gcc not giving preprocessor error for invalid invocation of variadic macro

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65547

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
And as has been documented forever, the way to get diagnostics for GNU
extensions that contradict the ISO standard is the -pedantic switch:

https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Warning-Options.html#index-pedantic-279

There is no bug here.