It seems that When I uninstalled an older version of the Windows 10 SDK to make more disk space to update Visual Studio that now python 3.6 will not compile. I am not sure if Python 3.7 on master currently has this issue or not though I still have not tested it on 3.7 either. I am using Visual Studio 2017 to Compile the latest commit on branch 3.6. I could technically use branch master if the issue with Py_DecodeLocale() is fixed yet though.
Apparently Tk has something in its e_capi.c file that does not work with the latest SDK (I guess they're redefining macros). In master, we use prebuilt binaries, which is why this is not a problem. But we'll either need to fix Tk's sources or backport the code that uses the prebuilt binaries (just for Tcl and Tk - the OpenSSL part is not compatible) before we can merge this. I'll try and take a look at it over the next few weeks. An a workaround, you should be able to "SET WindowsSDKVersion=10.0.16299.0" and pass "--no-tkinter" to build.bat to compile without the change.
