[Bug c++/79658] [-Wuninitialized] referencing uninitialized field of POD struct should warn

[palves at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79658

--- Comment #6 from Pedro Alves <palves at redhat dot com> ---
Created attachment 40807
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40807&action=edit
reproducer v3

Slightly reduced testcase.  enum_flags no longer a template, and
stores/uses/converts to int instead of enum type.  Same set of (missing)
warnings.