use xcode 7 to make MacOSX10.11.sdk available
use xcode 7 to make MacOSX10.11.sdk available

langateam/node-mapnik,mapnik/node-mapnik,CartoDB/node-mapnik,tomhughes/node-mapnik,CartoDB/node-mapnik,langateam/node-mapnik,CartoDB/node-mapnik,langateam/node-mapnik,CartoDB/node-mapnik,mapnik/node-mapnik,tomhughes/node-mapnik,mapnik/node-mapnik,mapnik/node-mapnik,mapnik/node-mapnik,tomhughes/node-mapnik,tomhughes/node-mapnik,CartoDB/node-mapnik,langateam/node-mapnik,langateam/node-mapnik,tomhughes/node-mapnik