[Python] pip install : unable to find vcvarsall.bat

If you are on Windows and get this message :

Unable to find vcvarsall.bat

when you type pip install greenlet (or another lib)

Then you must :
- install MinGW (after the installation, run the MinGW Installation Manager and install only these two packages : mingw32-base et mingw32-gcc-g++)
- add the mingw's bin directory to your path
- edit or create C:\PythonXX\Lib\distutils\distutils.cfg and write :

[build] 

compiler=mingw32

- open an new cmd and type again your pip install greenlet (or another lib)

Have fun
:o)