There might be `libint2` copies of easyconfig files out there that do not specify `sanity_check_paths`, and those will be broken (unless `libint2` provides a non-empty `bin` *and* `lib` dir, which is what EB checks by default).

If there is an easyblock, having a good default for `sanity_check_paths` there allows to remove at least 4 lines from the easyconfig, thus cleans things up.
Even if files differ across versions, I would still prefer adding a version check in the easyblock rather than copying all the sanity check paths to the easyconfigs... Those should be as clean as possible, imho.