[Bug libstdc++/58800] [4.7.4/4.8.2/4.9 Regression] std::nth_element segfaults on valid input

[chris at bubblescope dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58800

--- Comment #15 from Chris Jefferson <chris at bubblescope dot net> ---
In my last comment, "Obviously we couldn't de-ref 'last - 1'" should have been
"Obviously we couldn't de-ref 'last'"