Fixed compile for Python 3. There are still some crashes though.

python/google/protobuf/pyext/map_container.h

@@ -111,8 +111,16 @@ struct MessageMapContainer : public MapContainer {
   PyObject* message_dict;
 };
 
-extern PyTypeObject ScalarMapContainer_Type;
-extern PyTypeObject MessageMapContainer_Type;
+#if PY_MAJOR_VERSION >= 3
+  extern PyObject *MessageMapContainer_Type;
+  extern PyType_Spec MessageMapContainer_Type_spec;
+  extern PyObject *ScalarMapContainer_Type;
+  extern PyType_Spec ScalarMapContainer_Type_spec;
+#else
+  extern PyTypeObject MessageMapContainer_Type;
+  extern PyTypeObject ScalarMapContainer_Type;
+#endif
+
 extern PyTypeObject MapIterator_Type;  // Both map types use the same iterator.
 
 // Builds a MapContainer object, from a parent message and a

python/setup.py

@@ -162,7 +162,7 @@ if __name__ == '__main__':
     extra_compile_args = ['-Wno-write-strings', '-Wno-invalid-offsetof']
     test_conformance.target = 'test_python_cpp'
 
-    if "clang" in os.popen('$CC --version').read():
+    if "clang" in os.popen('$CC --version 2> /dev/null').read():
       extra_compile_args.append('-Wno-shorten-64-to-32')
 
     if warnings_as_errors in sys.argv: