provide is_substitute specialisation for  mapnik::geometry::linear_ring<double> const& (gcc6)
provide is_substitute specialisation for  mapnik::geometry::linear_ring<double> const& (gcc6)

naturalatlas/mapnik,mapnik/mapnik,tomhughes/mapnik,naturalatlas/mapnik,mapnik/mapnik,lightmare/mapnik,tomhughes/mapnik,lightmare/mapnik,tomhughes/mapnik,lightmare/mapnik,mapnik/mapnik,tomhughes/mapnik,naturalatlas/mapnik,mapnik/mapnik,naturalatlas/mapnik,lightmare/mapnik