Buildtools installation on python 3.6.4

[Larz60+]

I don't know why it works for you and not for me.
I built a virtual environment and keep everything inside:
I cannot find a distribution for make_admonition
Phoenix is latest (development) branch

λ python -m venv Phoenix
# Then download and unzip phoenix:
M:\python\m-p\p\Phoenix
λ Scripts\activate.bat
(Phoenix) λ ls
Include/  Lib/  Phoenix-master.zip  pyvenv.cfg  Scripts/
# Even make sure 7zip is in environment:
M:\python\m-p\p\Phoenix
(Phoenix) λ mkdir 7zip

M:\python\m-p\p\Phoenix
(Phoenix) λ cd 7zip

M:\python\m-p\p\Phoenix\7zip
(Phoenix) λ ls
7z.dll*  7z.sfx*          7zCon.sfx*  7zG.exe*   7-zip.dll*    descript.ion  Lang/        readme.txt
7z.exe*  7z1701-x64.exe*  7zFM.exe*   7-zip.chm  7-zip32.dll*  History.txt   License.txt  Uninstall.exe

M:\python\m-p\p\Phoenix
(Phoenix) λ ls
7zip/  Include/  Lib/  Phoenix-master/  pip-selfcheck.json  pyvenv.cfg  Scripts/

M:\python\m-p\p\Phoenix
(Phoenix) λ pip install -U pipenv
Collecting pipenv
...
Successfully installed certifi-2017.11.5 chardet-3.0.4 flake8-3.5.0 idna-2.6 mccabe-0.6.1 pew-1.1.2 pipenv-9.0.1 psutil-5.3.1 pycodestyle-2.3.1 pyflakes-1.6.0 requests-2.18.4 setuptools-38.4.0 urllib3-1.22 virtualenv-15.1.0 virtualenv-clone-0.2.6

M:\python\m-p\p\Phoenix
(Phoenix) λ pipenv install Sphinx
...
Successfully installed Jinja2-2.10 MarkupSafe-1.0 Pygments-2.2.0 Sphinx-1.6.5 alabaster-0.7.10 babel-2.5.1 colorama-0.3.9 docutils-0.14 imagesize-0.7.1 pytz-2017.3 six-1.11.0 snowballstemmer-1.2.1 sphinxcontrib-websupport-1.0.1

(Phoenix) λ cd M:\python\m-p\p\Phoenix\Phoenix-master\docs\sphinx

M:\python\m-p\p\Phoenix\Phoenix-master\docs\sphinx
(Phoenix) λ ls
_downloads/  _templates/      build/   itemToModuleMap.json  Makefile        rest_substitutions/
_static/     availability.py  conf.py  make.bat              phoenix_theme/

# change version and release in conf.py, and remove buildtools
(Phoenix) λ vi conf.py

M:\python\m-p\p\Phoenix\Phoenix-master\docs\sphinx
(Phoenix) λ make html
Running Sphinx v1.6.5
m:\python\m-p\p\phoenix\lib\site-packages\sphinx\util\compat.py:40: RemovedInSphinx17Warning: sphinx.util.compat.Directive is deprecated and will be removed in Sphinx 1.7, please use docutils' instead.
  RemovedInSphinx17Warning)

Extension error:
Could not import extension availability (exception: cannot import name 'make_admonition')

M:\python\m-p\p\Phoenix\Phoenix-master\docs\sphinx
(Phoenix) λ