python falls with an error when trying to build

[vldmitrofanov]

When I'm trying to run python build

$ python build.py
Cloning into 'build/f4se'...
remote: Enumerating objects: 145, done.
remote: Counting objects: 100% (145/145), done.
remote: Compressing objects: 100% (125/125), done.
remote: Total 3416 (delta 21), reused 38 (delta 17), pack-reused 3271
Receiving objects: 100% (3416/3416), 1.69 MiB | 794.00 KiB/s, done.
Resolving deltas: 100% (2612/2612), done.
Note: checking out 'tags/v0.6.19'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by performing another checkout.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:

  git checkout -b <new-branch-name>

HEAD is now at ff89443 0.6.19
F4SE Path: C:/Users/shirker/source/repos/mcm/build/f4se/src/f4se
Patched: 1/2
Project Path: src\build.vcxproj
Project Path: src\build.vcxproj
Traceback (most recent call last):
  File "tools/build-tools/build_plugin.py", line 67, in <module>
    os.environ['INCLUDE'] = '{};{};{}'.format(f4se_dir, src_dir, os.environ['INCLUDE'])
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Python36_64\lib\os.py", line 669, in __getitem__
    raise KeyError(key) from None
KeyError: 'INCLUDE'

python version 3.6.6 x64 os Win 7 SP1

any suggestion please?