Fix compilation issue in Windows CUDA 13.2 + VS 2026

[Fangzhou-Ai]

Compilaltione will fail with error info for latest CUDA + Visual studio

C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v13.2\bin/../include/cccl\cuda/std/__cccl/preprocessor.h(20): fatal error C1189: #error: MSVC/cl.exe with traditional preprocessor is used. This may lead to unexpected compilation errors. Please switch to the standard conforming preprocessor by passing /Zc:preprocessor to cl.exe. You can define CCCL_IGNORE_MSVC_TRADITIONAL_PREPROCESSOR_WARNING to suppress this warning.

Solution: add

if(WIN32)
    set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} \
        -Xcompiler=/Zc:preprocessor")
endif()