1-compile-install-texture-gen.bat fails with _addcarry_u64 - portable Python building as win32

[LandenGuthrie]

Windows 11, VS 2022, CUDA 12.9
Build always targets win32-cpython-312 instead of win-amd64
Error: _addcarry_u64 identifier not found
Tried: DISTUTILS_USE_SDK=1, MSSdk=1, MSVC v142, short path (D:\AI\Hunyuan3D)
Nothing overrides the win32 target