turn off unused warnings for gcc
turn off unused warnings for gcc

lucadelu/PDAL,Sciumo/PDAL,jwomeara/PDAL,radiantbluetechnologies/PDAL,Sciumo/PDAL,Sciumo/PDAL,jwomeara/PDAL,mtCarto/PDAL,mpgerlek/PDAL-old,mtCarto/PDAL,lucadelu/PDAL,verma/PDAL,boundlessgeo/PDAL,mpgerlek/PDAL-old,DougFirErickson/PDAL,DougFirErickson/PDAL,verma/PDAL,verma/PDAL,verma/PDAL,boundlessgeo/PDAL,lucadelu/PDAL,mtCarto/PDAL,boundlessgeo/PDAL,DougFirErickson/PDAL,jwomeara/PDAL,verma/PDAL,mpgerlek/PDAL-old,DougFirErickson/PDAL,mtCarto/PDAL,boundlessgeo/PDAL,radiantbluetechnologies/PDAL,mpgerlek/PDAL-old,verma/PDAL,Sciumo/PDAL,verma/PDAL,radiantbluetechnologies/PDAL,jwomeara/PDAL,radiantbluetechnologies/PDAL,lucadelu/PDAL