Add hardening flags to G++.
Add hardening flags to G++.

Using https://wiki.debian.org/Hardening to find a bunch of fun hardening flags
for G++.

dcode/stenographer,gconnell/stenographer,nbareil/stenographer,gconnell/stenographer,gconnell/stenographer,dcode/stenographer,dcode/stenographer,google/stenographer,nbareil/stenographer,google/stenographer,google/stenographer,nbareil/stenographer