[Bug c++/71290] [6/7 Regression] Flexible array member is not diagnosed with -pedantic

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71290

--- Comment #6 from Martin Sebor <msebor at gcc dot gnu.org> ---
I let this one slip through the cracks.  Patch posted for review:
https://gcc.gnu.org/ml/gcc-patches/2017-01/msg01983.html