Monkeypatch imp.find_module into the native modulefinder._find_module.

The modulefinder._find_module has an unpatched bug (python/cpython#84530) in py3.8, 3.9, 3.10.
Neither imp.find_module, nor the buggy modulefinder._find_module, handles namespace packages...

This fixes #130. #140, #141.

pydeps/mf27.py

@@ -1,5 +1,6 @@
 
 # from .mf.mf_next import *     # for debugging next version
+import modulefinder
 from modulefinder import (
     ModuleFinder as NativeModuleFinder
 )
@@ -12,6 +13,12 @@
 
 HAVE_ARGUMENT = dis.HAVE_ARGUMENT
 
+# monkey-patch broken modulefinder._find_module 
+# (https://github.com/python/cpython/issues/84530)
+# in Python 3.8-3.10
+if hasattr(modulefinder, '_find_module'):
+    modulefinder._find_module = imp.find_module
+
 
 class ModuleFinder(NativeModuleFinder):
     def import_hook(self, name, caller=None, fromlist=None, level=-1):