[Bug libstdc++/117121] [15 regression] heap-buffer-overflow in ranges::{copy,move}_backward for 1-element ranges

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117121

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I backported the changes to the algos and so had to backport this fix too.