[Bug testsuite/111883] Wstringop-overflow-6.C FAILs with -std=c++26

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111883

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I think Jakub wrote that code, but it looks like we just want the explicit
casts. I can add those.