CUDA: Fix CMAKE_CUDA_COMPILER_TOOLKIT_ROOT detection in Visual Studio
When using a Visual Studio generator, we do not know the path to
CMAKE_CUDA_COMPILER
until after the compiler id detection project
extracts it. However, based on the VS toolchain configuration we know
that the compiler id will be NVIDIA, so use that to drive the CUDA
architecture flag logic. After the main compiler id step we know
CMAKE_CUDA_COMPILER
, so CMAKE_CUDA_COMPILER_TOOLKIT_ROOT
can then be
computed.
Based on !4920 (merged).
Backport: release