--- Python-3.9.4/Lib/importlib/_bootstrap_external.py.orig	2021-04-07 19:17:30 +0000
+++ Python-3.9.4/Lib/importlib/_bootstrap_external.py	2021-04-07 19:19:46 +0000
@@ -1604,6 +1604,10 @@
     else:
         raise ImportError('importlib requires posix or nt')
 
+    if 'MSYSTEM' in os_module.environ:
+        path_separators = path_separators[::-1]
+        path_sep = path_separators[0]
+
     setattr(self_module, '_os', os_module)
     setattr(self_module, 'path_sep', path_sep)
     setattr(self_module, 'path_separators', ''.join(path_separators))