Issue #27959: Adds oem encoding, alias ansi to mbcs, move aliasmbcs to codec lookup

Lib/site.py

@@ -423,21 +423,6 @@ def enablerlcompleter():
 
     sys.__interactivehook__ = register_readline
 
-def aliasmbcs():
-    """On Windows, some default encodings are not provided by Python,
-    while they are always available as "mbcs" in each locale. Make
-    them usable by aliasing to "mbcs" in such a case."""
-    if sys.platform == 'win32':
-        import _bootlocale, codecs
-        enc = _bootlocale.getpreferredencoding(False)
-        if enc.startswith('cp'):            # "cp***" ?
-            try:
-                codecs.lookup(enc)
-            except LookupError:
-                import encodings
-                encodings._cache[enc] = encodings._unknown
-                encodings.aliases.aliases[enc] = 'mbcs'
-
 CONFIG_LINE = r'^(?P<key>(\w|[-_])+)\s*=\s*(?P<value>.*)\s*$'
 
 def venv(known_paths):
@@ -560,7 +545,6 @@ def main():
     setcopyright()
     sethelper()
     enablerlcompleter()
-    aliasmbcs()
     execsitecustomize()
     if ENABLE_USER_SITE:
         execusercustomize()