On Sun, 9 Jul 2017, Bruce Ferrell wrote:

> OK, before the flames start I KNOW it's not normal.
>
> Has anyone have a method to upgrade glibc beyond 2.12?

I've tried, but not succeeded so far, so would be interested
to hear from anyone else who has.

I would recommend *not* replacing glibc, but installing
the new version in a separate directory and using a wrapper
script to select the new glibc when required.

An example of one way to do this would be Richard Lloyd's
http://chrome.richardlloyd.org.uk/install_chrome.sh
This includes an rpm chrome-deps-stable
which has a libstdc++.so with GLIBCXX_3.21 and lower
for google chrome on SL6.
Chrome 59 requires gtk3, which is not available on SL6,
so Richard has arranged that the latest version *un*installs chrome.