also link to CUDA::cufft_static in case of BUILD_SHARED_LIBS=OFF

[gregorburger]

In case BUILD_SHARED_LIBS is disabled, the cufft library is still linked to the dynamic version, whereas all other cuda libraries are linked to the static versions by appending CUDA_LIB_EXT. This PR makes cufft handles the same way as all other cuda libraries.

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• I agree to contribute to the project under Apache 2 License.
• To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
• The PR is proposed to the proper branch
• There is a reference to the original bug report and related work
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  Patch to opencv_extra has the same branch name.
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[katharinaHochf]

In any case someone uses older cmake versions:
CUDA::cufft_static_nocallback starting in CUDA 9.2, requires CMake 3.23+

otherwise static linking does not work even with that fix.

https://cmake.org/cmake/help/latest/module/FindCUDAToolkit.html#cuda-toolkit-cufft

[gregorburger]

In any case someone uses older cmake versions: CUDA::cufft_static_nocallback starting in CUDA 9.2, requires CMake 3.23+

otherwise static linking does not work even with that fix.

https://cmake.org/cmake/help/latest/module/FindCUDAToolkit.html#cuda-toolkit-cufft

Should work with the latest changes as well. If the proper versions of cuda or cmake aren't met, it will fall back to dynamic libraries as was the behaviour previously.

[cudawarped]

LGTM 👍

[gregorburger]

@cudawarped I'm new to the OpenCV workflow, is there anything missing starting a build on the CI?

[cudawarped]

@cudawarped I'm new to the OpenCV workflow, is there anything missing starting a build on the CI?

No. One of the core maintainers needs to have time to check this is sensible before kicking off the CI. As this is the contrib repo this in not as high a priority.