[Bug driver/115293] Warn if a compiler flag downgrades protection provided by -fhardened

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115293

--- Comment #2 from Siddhesh Poyarekar <siddhesh at gcc dot gnu.org> ---
Oh, I had overlooked -Whardened; so it looks like we already do this.