And probably CFLAGS as well (where it cannot hurt). This will enable additional security hardening which performs range checking for operator[] in std::vector, std::string, and std::array.
The change was approved by Fesco. https://fedoraproject.org/wiki/Changes/HardeningFlags28 https://meetbot-raw.fedoraproject.org/fedora-meeting/2018-01-12/fesco.2018-01-12-16.00.log.html#l-201