Issue #2377: Make importlib the implementation of __import__().

importlib._bootstrap is now frozen into Python/importlib.h and stored
as _frozen_importlib in sys.modules. Py_Initialize() loads the frozen
code along with sys and imp and then uses _frozen_importlib._install()
to set builtins.__import__() w/ _frozen_importlib.__import__().
diff --git a/Include/abstract.h b/Include/abstract.h
index 4a27bfb..e879fa1b 100644
--- a/Include/abstract.h
+++ b/Include/abstract.h
@@ -339,6 +339,10 @@
 
      PyAPI_FUNC(PyObject *) PyObject_CallMethodObjArgs(PyObject *o,
                                                        PyObject *method, ...);
+     PyAPI_FUNC(PyObject *) _PyObject_CallMethodObjIdArgs(PyObject *o,
+                                               struct _Py_Identifier *method,
+                                               ...);
+
 
        /*
      Call the method named m of object o with a variable number of