Performing configure step for 'external_ispc'
  -- Selecting Windows SDK version 10.0.19041.0 to target Windows 10.0.19044.
  CMake Warning at cmake/FixWindowsPath.cmake:40 (message):
    Failed to find cygpath
  Call Stack (most recent call first):
    CMakeLists.txt:230 (include)


  -- Found LLVM LLVM_12_0
  -- LLVM_CONFIG_EXECUTABLE: C:/d/build/S/VS1564D/Debug/llvm/bin/llvm-config.exe
  -- CLANG_EXECUTABLE: C:/d/build/S/VS1564D/Debug/llvm/bin/clang
  -- CLANGPP_EXECUTABLE: C:/d/build/S/VS1564D/Debug/llvm/bin/clang++
  -- LLVM_DIS_EXECUTABLE: C:/d/build/S/VS1564D/Debug/llvm/bin/llvm-dis.exe
  -- LLVM_AS_EXECUTABLE: C:/d/build/S/VS1564D/Debug/llvm/bin/llvm-as.exe
  -- Using Debug VC++ CRT: MDd
  -- Using Release VC++ CRT: MD
  -- Using MinSizeRel VC++ CRT: MD
  -- Using RelWithDebInfo VC++ CRT: MD
  -- Using Debug VC++ CRT: MDd
  -- Detected LLVM version: 12.0.0
  CMake Warning at cmake/FindLLVM.cmake:134 (message):
    LLVM was built without assertions enabled (-DLLVM_ENABLE_ASSERTIONS=OFF).
    This disables dumps, which are required for ISPC to be fully functional.
  Call Stack (most recent call first):
    CMakeLists.txt:231 (include)


  -- GIT_BINARY: C:/Program Files/Git/cmd/git.exe
  fatal: not a git repository (or any of the parent directories): .git
  -- M4 macro processor: C:/d/build/downloads/mingw/mingw64/msys/1.0/bin/m4.exe
  CMake Error at C:/Program Files/CMake/share/cmake-3.22/Modules/FindPackageHandleStandardArgs.cmake:230 (message):
    Could NOT find Python3 (missing: Python3_EXECUTABLE Interpreter)
  Call Stack (most recent call first):
    C:/Program Files/CMake/share/cmake-3.22/Modules/FindPackageHandleStandardArgs.cmake:594 (_FPHSA_FAILURE_MESSAGE)
    C:/Program Files/CMake/share/cmake-3.22/Modules/FindPython/Support.cmake:3166 (find_package_handle_standard_args)
    C:/Program Files/CMake/share/cmake-3.22/Modules/FindPython3.cmake:490 (include)
    CMakeLists.txt:236 (find_package)


  -- Configuring incomplete, errors occurred!
  See also "C:/d/build/S/VS1564D/build/ispc/src/external_ispc-build/CMakeFiles/CMakeOutput.log".