Update CMakeLists.txt

CMakeLists.txt

@@ -9,8 +9,10 @@ set(CMAKE_CXX_STANDARD 11)
 message(STATUS "memory processing: GPU build in mode is ${INCLUDE_CUDA}")
 
 if(INCLUDE_CUDA)
+    if(NOT DEFINED CMAKE_CUDA_COMPILER)
         enable_language(CUDA)
         include_directories(${CMAKE_CUDA_TOOLKIT_INCLUDE_DIRECTORIES})
+    endif()
 
     # -DCMAKE_CUDA_ARCHITECTURES=native -- Compile for the architecture(s) of the host's GPU(s)
 endif(INCLUDE_CUDA)