target: missing -Whardened with -fcf-protection=none [PR114606]
-Whardened warns when -fhardened couldn't enable a hardening option
because that option was disabled on the command line, e.g.:
$ ./cc1plus -quiet g.C -fhardened -O2 -fstack-protector
cc1plus: warning: '-fstack-protector-strong' is not enabled by '-fhardened' because it was specified on the command line [-Whardened]
but it doesn't work as expected with -fcf-protection=none: