[Bug libstdc++/87855] std::optional only copy-constructible if T is trivially copy-constructible

[ville.voutilainen at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87855

--- Comment #5 from Ville Voutilainen <ville.voutilainen at gmail dot com> ---
New patch is at https://gcc.gnu.org/ml/gcc-patches/2018-11/msg01368.html