[Bug libstdc++/81964] istream_iterator: unexpected read in ctor

[abominable-snowman at yandex dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81964

--- Comment #2 from Petr Ovtchenkov <abominable-snowman at yandex dot ru> ---
https://gcc.gnu.org/ml/libstdc++/2017-08/msg00033.html