Drop GCC7 support
Drop GCC7 support

frodrigo/osrm-backend,Project-OSRM/osrm-backend,Project-OSRM/osrm-backend,Project-OSRM/osrm-backend,frodrigo/osrm-backend,frodrigo/osrm-backend,frodrigo/osrm-backend,Project-OSRM/osrm-backend