When compiling python 3.6.4 on appveyor using MSVC 2015 following error occurs.

(C:\bld\python_1514037886491\_b_env) C:\bld\python_1514037886491\work\Python-3.6.4\PCbuild>"C:\Program Files (x86)\MSBuild\14.0\Bin\amd64\MSBuild.exe"  "C:\bld\python_1514037886491\work\Python-3.6.4\PCbuild\pcbuild.proj" /t:Build /m /nologo /v:m /p:Configuration=Release /p:Platform=x64 /p:IncludeExternals=true /p:IncludeSSL=true /p:IncludeTkinter=true /p:UseTestMarker= /p:GIT="C:\Program Files\Git\cmd\git.exe"          
C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V140\Platforms\x64\PlatformToolsets\v140\Toolset.targets(36,5): error MSB8036: The Windows SDK version 10.0.15063.0 was not found. Install the required version of Windows SDK or change the SDK version in the project property pages or by right-clicking the solution and selecting "Retarget solution". [C:\bld\python_1514037886491\work\Python-3.6.4\PCbuild\pythoncore.vcxproj]

Note that appveyor Visual Studio 2015 image has only 10.0.10586, 10.0.14393 and 10.0.26624

Here's a simple patch that fixes this on 3.6 branch. 
https://github.com/isuruf/cpython/commit/9432a2c7f63b3bb55e8066e91eade81321154476
I haven't checked that the patch works on a machine with 10.0.15063