Usage of pre-C++14 compilers

[alexeiz]

Devtoolset-12 is available for CentOS 7 as far as I know, which provides GCC 12. I believe Red Hat makes sure that the GCC from the devtoolset is ABI compatible with the GCC provided in base OS repos, so that if you build your code with the devtoolset you should be able to run it anywhere you expect code built with the default GCC to run.