We must remove the 'libgcc' & 'libstdc++' libraries that ship with steam, as they are outdated & incompatible with the latest versions that ship with your OS (which your latest mesa drivers require).

Simply paste this into your terminal. Make sure you understand what it does before hitting enter, as this command indefinately & recursively removes files from your filesystem under your user's .steam directory.

cd ~/.steam ; rm -r $(find -L . | grep 'libgcc\|libstdc++') ; cd

This should only be required if you're running an AMD card. Nvidia users may need to look elsewhere.

For more info & the original solution, see the following reddit posts:

Unable to start Insurgency on kubuntu 17.10 fresh install