only nuke the files in ./lib on clean for 'make clean', not the lib directory itself
only nuke the files in ./lib on clean for 'make clean', not the lib directory itself

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