[Bug c/107980] va_start does not warn about an arbitrary number of arguments in C2x mode

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107980

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Why do you need a builtin for counting number of arguments in __VA_OPT__?
That can be done in the preprocessor.  All one needs is 1, 2 or more arguments.