CMake cl.exe -- broken on Windows 10 because simple test program could not be build

Hi devs!

So this one is a really weird bug I haven't manage to fix myself and even after reinstalling Windows, I'm now condfident enought to report it. In short I cannot setup any cmake project even with the most recent software. It simply broke last wednesday after using it for weeks without any hint why.

CMake thinks my c compiler is broken:

-- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.25.28610/bin/HostX64/x64/cl.exe -- broken
CMake Error at C:/Qt/Tools/CMake_64/share/cmake-3.16/Modules/CMakeTestCCompiler.cmake:60 (message):
  The C compiler

    "C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.25.28610/bin/HostX64/x64/cl.exe"

  is not able to compile a simple test program.

  It fails with the following output:

    Change Dir: C:/Users/Kelteseth/AppData/Local/Temp/QtCreator-KrkRfv/qtc-cmake-UWrpKkLg/CMakeFiles/CMakeTmp
    
    Run Build Command(s):jom /nologo cmTC_6ef38\fast && Das System kann die angegebene Datei nicht finden
    Generator: execution of make failed. Make command was: jom /nologo cmTC_6ef38\fast && 

Old Windows 10 setup before reinstalling:

• Visual studio 16.4, 16.5 and 16.6 preview
• Installing everything related to sdk, cmake, build, c++
• ninja 1.9, 1.10
• cmake 3.16, 3.17
• 4x most recent version of the Windows SDK
• Removing stuff in my environment variables
• Rebooting 1 billion times (or less)
• Opening QtCreator with a bash from Developer Command Promt

Freshly installed Windows 10 this morning setup. Installed only the following apps:

• vlc-3.0.8-win64.exe
• cmake-3.17.1-win64-x64.msi
• 7z1900-x64.exe
• SteamSetup.exe
• GitExtensions-3.3.1.7897.msi
• Git-2.26.1-64-bit.exe
• qt-unified-windows-x86-3.2.2-online.exe
• KeePass-2.44-Setup.exe
• affinity-designer-1.8.3.exe
• vs_community__1208671413.1587381300.exe
• VSCodeUserSetup-x64-1.44.2.exe
• win10-radeon-software-adrenalin-2020-edition-20.4.1-apr2.exe
• Firefox Installer.exe
• MSVC 2019 16.5.4 (Desktop development with c++ selected with Windows 10 SDK 10.0.18362.0)
• cmake 3.16 (via Qt Maintantance), 3.17.1
• QtCreator 4.11 and 4.12

Using CMake-gui works
With the new setup a plain cmake projects works (Hostx64/x64/cl.exe - works) see EmptyCMakeTest.zip. With QtCreator it still gives the same error message of – broken cl.exe.

I have attached the CMakeOutput.log and CMakeError.log from my reinstalled windows. Also qtc-cmake-UWrpKkLg.zip the where generated with two

• CMakeCXXCompilerId.exe // Can execute
• CMakeCCompilerId.exe // Cannot start

If you need any more info let me know. I'm also able to show this issue via TeamViewer or Anydesk.

Cheers!