Fixes qt configure errors with external openssl on older systems (rhel7) See efc02f9cc3/dist/changes-5.15.0 (L346) This means for now on, `qt ^openssl@1.0` gets you `qt@5.15.4 ~ssl`: clingo chooses latest qt version **but disables ssl support**.
efc02f9cc3/dist/changes-5.15.0 (L346)