@@ -59,19 +59,24 @@ class struct_frozen(Structure):
         items = []
         # _frozen_importlib changes size whenever importlib._bootstrap
         # changes, so it gets a special case.  We should make sure it's
-        # found, but don't worry about its size too much.
-        _fzn_implib_seen = False
+        # found, but don't worry about its size too much.  The same
+        # applies to _frozen_importlib_external.
+        bootstrap_seen = []
+        bootstrap_expected = (
+                b'_frozen_importlib',
+                b'_frozen_importlib_external',
+                )
         for entry in ft:
             # This is dangerous. We *can* iterate over a pointer, but
             # the loop will not terminate (maybe with an access
             # violation;-) because the pointer instance has no size.
             if entry.name is None:
                 break
 
-            if entry.name == b'_frozen_importlib':
-                _fzn_implib_seen = True
+            if entry.name in bootstrap_expected:
+                bootstrap_seen.append(entry.name)
                 self.assertTrue(entry.size,
-                    "_frozen_importlib was reported as having no size")
+                    "{} was reported as having no size".format(entry.name))
                 continue
             items.append((entry.name, entry.size))
 
@@ -81,8 +86,8 @@ class struct_frozen(Structure):
                     ]
         self.assertEqual(items, expected)
 
-        self.assertTrue(_fzn_implib_seen,
-            "_frozen_importlib wasn't found in PyImport_FrozenModules")
+        self.assertEqual(sorted(bootstrap_seen), bootstrap_expected,
+            "frozen bootstrap modules did not match PyImport_FrozenModules")
 
         from ctypes import _pointer_type_cache
         del _pointer_type_cache[struct_frozen]
 
@@ -16,7 +16,8 @@
     # Platform doesn't support dynamic loading.
     load_dynamic = None
 
-from importlib._bootstrap import SourcelessFileLoader, _ERR_MSG, _exec, _load
+from importlib._bootstrap import _ERR_MSG, _exec, _load
+from importlib._bootstrap_external import SourcelessFileLoader
 
 from importlib import machinery
 from importlib import util
 
@@ -30,9 +30,25 @@
         pass
     sys.modules['importlib._bootstrap'] = _bootstrap
 
+try:
+    import _frozen_importlib_external as _bootstrap_external
+except ImportError:
+    from . import _bootstrap_external
+    _bootstrap_external._setup(_bootstrap)
+else:
+    _bootstrap_external.__name__ = 'importlib._bootstrap_external'
+    _bootstrap_external.__package__ = 'importlib'
+    try:
+        _bootstrap_external.__file__ = __file__.replace('__init__.py', '_bootstrap_external.py')
+    except NameError:
+        # __file__ is not guaranteed to be defined, e.g. if this code gets
+        # frozen by a tool like cx_Freeze.
+        pass
+    sys.modules['importlib._bootstrap_external'] = _bootstrap_external
+
 # To simplify imports in test code
-_w_long = _bootstrap._w_long
-_r_long = _bootstrap._r_long
+_w_long = _bootstrap_external._w_long
+_r_long = _bootstrap_external._r_long
 
 # Fully bootstrapped at this point, import whatever you like, circular
 # dependencies and startup overhead minimisation permitting :)