Allow c++20 in nvcc_wrapper for nvcc 12 and above

bin/nvcc_wrapper

@@ -338,6 +338,24 @@ do
     std_flag=$corrected_std_flag
     shared_args="$shared_args $std_flag"
     ;;
+  --std=c++20|-std=c++20)
+    if [ -n "$std_flag" ]; then
+      warn_std_flag
+      shared_args=${shared_args/ $std_flag/}
+    fi
+    # NVCC only has C++20 from version 12 on
+    cuda_main_version=$([[ $(${nvcc_compiler} --version) =~ V([0-9]+) ]] && echo ${BASH_REMATCH[1]})
+    if [ ${cuda_main_version} -lt 12 ]; then
+      fallback_std_flag="-std=c++14"
+      # this is hopefully just occurring in a downstream project during CMake feature tests
+      # we really have no choice here but to accept the flag and change  to an accepted C++ standard
+      echo "nvcc_wrapper does not accept standard flags $1 since partial standard flags and standards after C++14 are not supported. nvcc_wrapper will use $fallback_std_flag instead. It is undefined behavior to use this flag. This should only be occurring during CMake configuration."
+      std_flag=$fallback_std_flag
+    else
+      std_flag=$1
+    fi
+    shared_args="$shared_args $std_flag"
+    ;;
   --std=c++17|-std=c++17)
     if [ -n "$std_flag" ]; then
       warn_std_flag