1. Install VS Build Tools using PortableBuildTools
   https://github.com/Data-Oriented-House/PortableBuildTools

2. for version 14.44.17.14 it creates devcmd.bat in the vs_BuildTools folder

   • copy this devcmd.bat to VC\vcvarsall.bat
   • in vcvarsall.bat create an environment variable LIBPATH and set it to the same value as LIB
     (query_vcvarsall in distuils msvc9compiler needs LIBPATH in addition to LIB)

3. set VS140COMNTOOLS to the vs_BuildTools\VC\Tools folder
   (this makes sure vcvarsall.bat is being found by distutils)

4. set DISTUTILS_USE_SDK=1 / $env:DISTUTILS_USE_SDK=1
   execute devcmd.bat / devcmd.ps1

Steps 3 and 4 can be included in devcmd.bat:

set VS140COMNTOOLS=%BUILD_TOOLS_ROOT%VC\Tools
set DISTUTILS_USE_SDK=1 

or devcmd.ps1:

$env:VS140COMNTOOLS =  (Join-Path $InstallPath '\VC\Tools')
$env:DISTUTILS_USE_SDK = 1  

Now you can install packages from source with cython, e.g. pip install outliertree