[llvm] [offload] Add Windows offload support (PR #187006)

[Weronika Lewandowska via llvm-commits]

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@@ -305,6 +305,7 @@ function(runtime_default_target)
                                                 CUDA CMAKE_CUDA # For runtimes that may look for the CUDA compiler and/or SDK (libc, offload, flang-rt)
                                                 FFI # offload uses libffi
                                                 FLANG_RUNTIME # Shared between Flang and Flang-RT
+                                                LIBOMPTARGET # offload plugin selection
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wlemkows wrote:

@Meinersbur please review here: https://github.com/llvm/llvm-project/pull/199906

https://github.com/llvm/llvm-project/pull/187006