Buildbot flang-runtime-cuda-gcc uses CMAKE_CUDA_*

Needs to be propagated to runtime in order to continue to work.

Author: Meinersbur

llvm/runtimes/CMakeLists.txt

@@ -277,7 +277,7 @@ function(runtime_default_target)
                                       ${ARG_CMAKE_ARGS}
                            PASSTHROUGH_PREFIXES LLVM_ENABLE_RUNTIMES
                                                 LLVM_USE_LINKER
-                                                CUDA # For runtimes that may look for the CUDA SDK (libc, offload, flang-rt)
+                                                CUDA CMAKE_CUDA # For runtimes that may look for the CUDA compiler and/or SDK (libc, offload, flang-rt)
                                                 FLANG_RUNTIME # Shared between Flang and Flang-RT
                                                 ${ARG_PREFIXES}
                            EXTRA_TARGETS ${extra_targets}