[Bug c++/64236] [c++11] last alignas overrides stricter on a class definition

[glaubitz at physik dot fu-berlin.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64236

--- Comment #5 from John Paul Adrian Glaubitz <glaubitz at physik dot 
fu-berlin.de> ---
Still reproducible on gcc-7 (r243972).