Fixes to CUDA's select_system and SConstruct on Windows

SConstruct

@@ -343,6 +343,7 @@ elif master_env['PLATFORM'] == 'darwin':
   master_env['ENV'].setdefault('DYLD_LIBRARY_PATH', []).append(cuda_installation()[1])
 elif master_env['PLATFORM'] == 'win32':
   master_env['ENV']['TBBROOT'] = os.environ['TBBROOT']
+  master_env['ENV']['PATH'] += ';' + tbb_installation(master_env)[0]
 
 # get the list of requested backends
 host_backends = master_env.subst('$host_backend').split()

thrust/system/cuda/detail/tag.h

@@ -57,20 +57,34 @@ inline Tag select_system(thrust::any_system_tag, Tag)
   return Tag();
 }
 
+// this version catches a user's tag derived from cuda::tag in the first slot
 template<typename Tag>
 __host__ __device__
 inline cuda_to_cpp select_system(Tag, thrust::system::cpp::tag)
 {
   return cuda_to_cpp();
 }
 
+__host__ __device__
+inline cuda_to_cpp select_system(tag, thrust::system::cpp::tag)
+{
+  return cuda_to_cpp();
+}
+
+// this version catches a user's tag derived from cuda::tag in the second slot
 template<typename Tag>
 __host__ __device__
 inline cpp_to_cuda select_system(thrust::system::cpp::tag, Tag)
 {
   return cpp_to_cuda();
 }
 
+__host__ __device__
+inline cpp_to_cuda select_system(thrust::system::cpp::tag, tag)
+{
+  return cpp_to_cuda();
+}
+
 } // end detail
 
 // alias the tag here