Merge pull request matplotlib#733 from mdboom/clang-py3-fixes

Issues compiling with clang + Python 3.x

Author: mdboom

CXX/Python3/Objects.hxx

@@ -413,7 +413,7 @@ namespace Py
         {
         }
 
-        bool accepts( PyObject *pyob )
+        virtual bool accepts( PyObject *pyob ) const
         {
             return pyob == NULL;
         }
@@ -1520,7 +1520,7 @@ namespace Py
 
             int operator-( const iterator &other ) const
             {
-                if( seq.ptr() != other.seq.ptr() )
+              if( seq->ptr() != other.seq->ptr() )
                     throw RuntimeError( "SeqBase<T>::iterator comparison error" );
 
                 return count - other.count;