Win + Python3.6で「pip install」を実行したときに「UnicodeDecodeError: 'utf-8' codec can't decode byte 0x83」と表示される。

#環境
- Windows 10
- Python3.6

#事象
「pip install」を実行したときに、「UnicodeDecodeError: 'utf-8' codec can't decode byte 0x83」というエラーメッセージが表示される。

#対応策
1.
pip\compat\\\_\_init\_\_.py (環境によって場所は違う。下記エラーメッセージ例の1つめのハイライト箇所が指す\_\_init\_\_.pyを編集すること)をテキストエディタで開く。

2.
ファイル冒頭部分の

```py:compat\__init__.py
import os
import sys
```
を

```py:compat\__init__.py
import os
import sys
import locale
```

とする。

3.

```py:compat\__init__.py
if sys.version_info >= (3,):
    def console_to_str(s):
        try:
            return s.decode(sys.__stdout__.encoding)
        except UnicodeDecodeError:
            return s.decode('utf_8')
```

を

```py:compat\__init__.py
if sys.version_info >= (3,):
    def console_to_str(s):
        # try:
        #     return s.decode(sys.__stdout__.encoding)
        # except UnicodeDecodeError:
        #     return s.decode('utf_8')
        return s.decode(locale.getpreferredencoding() or "utf-8", 'replace')
```
と変更する。

4.
保存する。

###該当のエラーメッセージ例

```bat:pipinstall 
(C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow) C:\Users\name_>pip install cupy
Collecting cupy
  Using cached cupy-2.0.0.tar.gz
Exception:
Traceback (most recent call last):
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\compat\__init__.py", line 73, in console_to_str
    return s.decode(sys.__stdout__.encoding)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x83 in position 95: invalid start byte

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\commands\install.py", line 335, in run
    wb.build(autobuilding=True)
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\wheel.py", line 749, in build
    self.requirement_set.prepare_files(self.finder)
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\req\req_set.py", line 380, in prepare_files
    ignore_dependencies=self.ignore_dependencies))
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\req\req_set.py", line 634, in _prepare_file
    abstract_dist.prep_for_dist()
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\req\req_set.py", line 129, in prep_for_dist
    self.req_to_install.run_egg_info()
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\req\req_install.py", line 439, in run_egg_info
    command_desc='python setup.py egg_info')
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\utils\__init__.py", line 676, in call_subprocess
    line = console_to_str(proc.stdout.readline())
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\compat\__init__.py", line 75, in console_to_str
    return s.decode('utf_8')
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x83 in position 95: invalid start byte

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\basecommand.py", line 215, in main
    status = self.run(options, args)
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\commands\install.py", line 385, in run
    requirement_set.cleanup_files()
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\utils\build.py", line 38, in __exit__
    self.cleanup()
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\utils\build.py", line 42, in cleanup
    rmtree(self.name)
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\_vendor\retrying.py", line 49, in wrapped_f
    return Retrying(*dargs, **dkw).call(f, *args, **kw)
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\_vendor\retrying.py", line 212, in call
    raise attempt.get()
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\_vendor\retrying.py", line 247, in get
    six.reraise(self.value[0], self.value[1], self.value[2])
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\six.py", line 686, in reraise
    raise value
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\_vendor\retrying.py", line 200, in call
    attempt = Attempt(fn(*args, **kwargs), attempt_number, False)
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\utils\__init__.py", line 102, in rmtree
    onerror=rmtree_errorhandler)
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\shutil.py", line 494, in rmtree
    return _rmtree_unsafe(path, onerror)
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\shutil.py", line 384, in _rmtree_unsafe
    _rmtree_unsafe(fullname, onerror)
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\shutil.py", line 393, in _rmtree_unsafe
    onerror(os.rmdir, path, sys.exc_info())
  File "C:\Users\name_\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\pip\utils\__init__.py", line 114, in rmtree_errorhandler
    func(path)
PermissionError: [WinError 32] プロセスはファイルにアクセスできません。別のプロセスが使用中です。: 'C:\\Users\\name_\\AppData\\Local\\Temp\\pip-build-gtomq_do\\cupy'
```

#参考
- [Python 3.x - Python3.6.1を用いてScrapyをインストールしたいがエラーが大量にでてインストールできない。(74061)｜teratail](https://teratail.com/questions/74061)
- [try fix encode error #4251 by robinxb · Pull Request #4280 · pypa/pip](https://github.com/pypa/pip/pull/4280/files)