https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119842
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
By worked I mean we emitted a warning:
```
<source>:3:5: warning: conflicting types for built-in function 'vfprintf';
expected 'int(void *, const char *, __va_list_tag *)'
[-Wbuiltin-declaration-mismatch]
3 | int vfprintf (void * , char * , struct a *);
| ^~~~~~~~
```
