[Bug libstdc++/91516] Please also export the base object constructor for __shared_ptr;

[rafael at espindo dot la]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91516

--- Comment #1 from Rafael Avila de Espindola <rafael at espindo dot la> ---
Corresponding clang bug:

https://bugs.llvm.org/show_bug.cgi?id=43079