Re: Timo - is the v2.3.15 GCC limitation really necessarily or it's just a bug?

You can use Developer Toolset. It comes with newer GCC versions. I don't know the precise CentOS repository layout, but there is a devtoolset-7-gcc package somewhere.

SCL is included with CentOS, see:

https://www.softwarecollections.org/en/scls/rhscl/devtoolset-7/ https://www.softwarecollections.org/en/scls/rhscl/devtoolset-8/

As CentOS 6 is end of life you could find packages here: https://vault.centos.org/6.10/sclo/x86_64/rh/Packages/d/

Best regards Gerald