[Bug c/81117] Improve buffer overflow checking in strncpy

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81117

--- Comment #15 from Martin Sebor <msebor at gcc dot gnu.org> ---
(In reply to Dmitry G. Dyachenko from comment #12)

LTO doesn't interact with these warnings very well.  pr71907 and pr79062 track
a couple of the problems I know about.  If you find a different issue please do
open a new bug.