I think 14.04 is closer to 2.12 than 16.04

The target I've used was CentOS 6, mainly because it's the one that wasn't EOL yet. Although at the end of this year it will be, so I think it would be worth to upgrade the glibc version to the one used by CentOS 7 (2.17). Ubuntu 16 has a "too recent" glibc version (2.23).