[cleanup] Remove unused code paths (#2173)

Notes:

* `_windows_write_string`: Fixed in 3.6
  * https://bugs.python.org/issue1602
  * PEP: https://www.python.org/dev/peps/pep-0528

* Windows UTF-8 fix: Fixed in 3.3
  * https://bugs.python.org/issue13216

* `__loader__`: is always present in 3.3+
  * https://bugs.python.org/issue14646

* `workaround_optparse_bug9161`: Fixed in 2.7
  * https://bugs.python.org/issue9161

Authored by: fstirlitz

yt_dlp/__init__.py

@@ -5,7 +5,6 @@ f'You are using an unsupported version of Python. Only Python versions 3.6 and a
 
 __license__ = 'Public Domain'
 
-import codecs
 import io
 import itertools
 import os
@@ -18,7 +17,6 @@ from .compat import (
     compat_getpass,
     compat_os_name,
     compat_shlex_quote,
-    workaround_optparse_bug9161,
 )
 from .cookies import SUPPORTED_BROWSERS, SUPPORTED_KEYRINGS
 from .utils import (
@@ -807,13 +805,6 @@ def parse_options(argv=None):
 
 
 def _real_main(argv=None):
-    # Compatibility fixes for Windows
-    if sys.platform == 'win32':
-        # https://github.com/ytdl-org/youtube-dl/issues/820
-        codecs.register(lambda name: codecs.lookup('utf-8') if name == 'cp65001' else None)
-
-    workaround_optparse_bug9161()
-
     setproctitle('yt-dlp')
 
     parser, opts, all_urls, ydl_opts = parse_options(argv)