Cygwinにpyenvをインストールした時の奮戦記

$ git clone https://github.com/pyenv/pyenv.git ~/.pyenv

$ echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bash_bashrc
$ echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bash_bashrc
$ echo 'eval "$(pyenv init -)"' >> ~/.bash_bashrc
$ source ~/.bash_bashrc

$ pyenv install --list
Available versions:
  2.1.3
  2.2.3
  2.3.7
　以下略

$ pyenv install 3.7.6
Downloading Python-3.7.6.tar.xz...
-> https://www.python.org/ftp/python/3.7.6/Python-3.7.6.tar.xz
Installing Python-3.7.6...
WARNING: The Python bz2 extension was not compiled. Missing the bzip2 lib?
WARNING: The Python sqlite3 extension was not compiled. Missing the SQLite3 lib?
Installed Python-3.7.6 to /home/xxxx/.pyenv/versions/3.7.6

$ pyenv install 3.6.10
Downloading Python-3.6.10.tar.xz...
-> https://www.python.org/ftp/python/3.6.10/Python-3.6.10.tar.xz
Installing Python-3.6.10...

BUILD FAILED (CYGWIN_NT-6.1 3.1.2(0.340/5/3) using python-build 1.2.16-1-g4500a33c)

Inspect or clean up the working tree at /tmp/python-build.20200114100336.19695
Results logged to /tmp/python-build.20200114100336.19695.log

Last 10 log lines:
     PyStructSequence_SET_ITEM(result, 6, PyLong_FromLong(si->si_band));
                                                              ^
./Include/tupleobject.h:62:75: 備考: in definition of macro ‘PyTuple_SET_ITEM’
 #define PyTuple_SET_ITEM(op, i, v) (((PyTupleObject *)(op))->ob_item[i] = v)
                                                                           ^
./Modules/signalmodule.c:979:5: 備考: in expansion of macro ‘PyStructSequence_SET_ITEM’
     PyStructSequence_SET_ITEM(result, 6, PyLong_FromLong(si->si_band));
     ^~~~~~~~~~~~~~~~~~~~~~~~~
make: *** [Makefile:1782: Modules/signalmodule.o] エラー 1
make: *** 未完了のジョブを待っています....

◎python-3.6.10の./Modules/signalmodule.cでエラーになった箇所
    PyStructSequence_SET_ITEM(result, 6, PyLong_FromLong(si->si_band));

◎python-3.7.6の./Modules/signalmodule.cで同じ場所
#ifdef HAVE_SIGINFO_T_SI_BAND
    PyStructSequence_SET_ITEM(result, 6, PyLong_FromLong(si->si_band));
#else
    PyStructSequence_SET_ITEM(result, 6, PyLong_FromLong(0L));
#endif

$ pyenv install -k 3.6.10　　　*1
⇒ エラーになるが、$PYENV_ROOT/sources/3.6.10 にダウンロードした Python-3.6.10.tar.xz が残る。
［手操作］ Python-3.6.10.tar.xz を適当な場所で、解凍・展開。
　　　エラーになった./Modules/signalmodule.cをpython-3.7.6のコードのように修正し、
　　　新たなPython-3.6.10.tar.xzを作成する。
$ mkdir $PYENV_ROOT/cache　　　*2
［手操作］先ほど新たに作成した Python-3.6.10.tar.xz を $PYENV_ROOT/cache にコピーする。
$ PYTHON_BUILD_CACHE_PATH=$PYENV_ROOT/cache pyenv install 3.6.10　　　*3

$ pyenv help install
Usage: pyenv install [-f] [-kvp] <version>
       pyenv install [-f] [-kvp] <definition-file>
       pyenv install -l|--list
       pyenv install --version

  -l/--list          List all available versions
  -f/--force         Install even if the version appears to be installed already
  -s/--skip-existing Skip if the version appears to be installed already

  python-build options:

  -k/--keep          Keep source tree in $PYENV_BUILD_ROOT after installation
                     (defaults to $PYENV_ROOT/sources)
  -p/--patch         Apply a patch from stdin before building
  -v/--verbose       Verbose mode: print compilation status to stdout
  --version          Show version of python-build
  -g/--debug         Build a debug version

$ pyenv install 3.8.1
Downloading Python-3.8.1.tar.xz...
-> https://www.python.org/ftp/python/3.8.1/Python-3.8.1.tar.xz
Installing Python-3.8.1...
Installed Python-3.8.1 to /home/xxxx/.pyenv/versions/3.8.1

$ pyenv versions
* system (set by /home/xxxx/.pyenv/version)
  3.7.6
  3.8.1

$ pyenv global 3.8.1

$ pyenv versions
  system
  3.7.6
* 3.8.1 (set by /home/xxxx/.pyenv/version)

$ python -V
Python 2.7.16

$ pyenv which python
/usr/bin/python

◎python 3.7.6 に対するシンボリックリンク

$ cd $PYENV_ROOT/versions/3.7.6
$ ln -s easy_install-3.7 easy_install
$ ln -s idle3.7 idle
$ ln -s pip3.7 pip
$ ln -s pydoc3.7 pydoc
$ ln -s python3.7m.exe python
$ ln -s python3.7-config python-config

◎python 3.8.1 に対するシンボリックリンク

$ cd $PYENV_ROOT/versions/3.8.1
$ ln -s easy_install-3.8 easy_install
$ ln -s idle3.8 idle
$ ln -s pip3.8 pip
$ ln -s pydoc3.8 pydoc
$ ln -s python3.8.exe python-buildpython
$ ln -s python3.8-config python-config

$ pyenv init
$ pyenv rehash

$ pyenv global 3.7.6
$ pyenv versions
  system
* 3.7.6 (set by /home/xxxx/.pyenv/version)
  3.8.1
$ python -V
Python 3.7.6
$ pyenv which python
/home/xxxx/.pyenv/versions/3.7.6/bin/python

$ pyenv global 3.8.1
$ pyenv versions
  system
  3.7.6
* 3.8.1 (set by /home/xxxx/.pyenv/version)
$ python -V
Python 3.8.1
$ pyenv which python
/home/xxxx/.pyenv/versions/3.8.1/bin/python

$ pyenv global system
$ pyenv versions
* system (set by /home/xxxx/.pyenv/version)
  3.7.6
  3.8.1
$ python -V
Python 2.7.16
$ pyenv which python
/usr/bin/python