[Bug c/118403] uninitialized warning with automatic union

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118403

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Using `{}` is the correct fix. The referenced part of the C standard here is
applying to struct and not unions.