diff -up matplotlib-1.5.1/setupext.py.six matplotlib-1.5.1/setupext.py

--- matplotlib-1.5.1/setupext.py.six	2016-01-10 23:20:20.000000000 +0100

+++ matplotlib-1.5.1/setupext.py	2016-05-18 13:44:21.534494158 +0200

@@ -1026,6 +1026,18 @@ class Qhull(SetupPackage):

             ext.sources.extend(glob.glob('extern/qhull/*.c'))

+class Six(SetupPackage):

+    name = "six"

+

+    def check(self):

+        try:

+            import six

+        except ImportError:

+            return 'not found. pip may install it below.'

+

+        return 'version %s' % six.__version__

+

+

 class TTConv(SetupPackage):

     name = "ttconv"

diff -up matplotlib-1.5.1/setup.py.six matplotlib-1.5.1/setup.py

--- matplotlib-1.5.1/setup.py.six	2016-01-10 23:20:20.000000000 +0100

+++ matplotlib-1.5.1/setup.py	2016-05-18 13:44:21.528494040 +0200

@@ -84,7 +84,7 @@ mpl_packages = [

     setupext.Delaunay(),

     setupext.QhullWrap(),

     setupext.Tri(),

-    setupext.Externals(),

+    setupext.Six(),

     'Optional subpackages',

     setupext.SampleData(),

     setupext.Toolkits(),