[Bug libstdc++/68200] g++ 5.2 optimizes out pointer assignment in libstdc++ mt_allocator freelist destructor, causing crash at global-dtor time

[oremanj at mit dot edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68200

--- Comment #1 from Joshua Oreman <oremanj at mit dot edu> ---
Correction: the original bug was PR 52604, not PR 52064.