Support LIB_DIR_NAME environment variable for custom mapniklibpath
Support LIB_DIR_NAME environment variable for custom mapniklibpath

mapnik/python-mapnik,tomhughes/python-mapnik,mapycz/python-mapnik,tomhughes/python-mapnik,mapnik/python-mapnik,mapycz/python-mapnik,mapnik/python-mapnik,tomhughes/python-mapnik