[Bug c++/71912] flexible array in union

[drepper.fsp+rhbz at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71912

--- Comment #2 from drepper.fsp+rhbz at gmail dot com <drepper.fsp+rhbz at gmail dot com> ---
If it is accepted that this code should work (as I also expect) then this bug
should also be marked as a regression to 5.x.  6.1 at least is broken, I don't
know when it stopped working.