Disable auto-pickling for some internal modules to reduce their code overhead.

Cython/Compiler/Scanning.py

-# cython: infer_types=True, language_level=3, py2_import=True
+# cython: infer_types=True, language_level=3, py2_import=True, auto_pickle=False
 #
 #   Cython Scanner
 #
@@ -63,6 +63,12 @@ class Method(object):
         # self.kwargs is almost always unused => avoid call overhead
         return method(text, **self.kwargs) if self.kwargs is not None else method(text)
 
+    def __copy__(self):
+        return self  # immutable, no need to copy
+
+    def __deepcopy__(self, memo):
+        return self  # immutable, no need to copy
+
 
 #------------------------------------------------------------------
 
@@ -188,6 +194,12 @@ class SourceDescriptor(object):
         except AttributeError:
             return False
 
+    def __copy__(self):
+        return self  # immutable, no need to copy
+
+    def __deepcopy__(self, memo):
+        return self  # immutable, no need to copy
+
 
 class FileSourceDescriptor(SourceDescriptor):
     """

Cython/Runtime/refnanny.pyx

-# cython: language_level=3
+# cython: language_level=3, auto_pickle=False
 
 from cpython.ref cimport PyObject, Py_INCREF, Py_DECREF, Py_XDECREF, Py_XINCREF
 from cpython.exc cimport PyErr_Fetch, PyErr_Restore