cmake: allow multiple CUDA architectures

In order to properly specify multiple CUDA architectures, we must quote
the variable so that cmake does not interpret it as multiple arguments
to `set_target_properties`.

src/cuda/CMakeLists.txt

@@ -43,7 +43,7 @@ target_include_directories(cufinufft_common_objects
 set_target_properties(
   cufinufft_common_objects
   PROPERTIES POSITION_INDEPENDENT_CODE ${FINUFFT_SHARED_LINKING}
-             CUDA_ARCHITECTURES ${FINUFFT_CUDA_ARCHITECTURES}
+             CUDA_ARCHITECTURES "${FINUFFT_CUDA_ARCHITECTURES}"
              CUDA_SEPARABLE_COMPILATION ON
              CUDA_STANDARD 17
              CUDA_STANDARD_REQUIRED ON)
@@ -60,7 +60,7 @@ target_include_directories(cufinufft_objects PUBLIC ${CUFINUFFT_INCLUDE_DIRS})
 set_target_properties(
   cufinufft_objects
   PROPERTIES POSITION_INDEPENDENT_CODE ${FINUFFT_SHARED_LINKING}
-             CUDA_ARCHITECTURES ${FINUFFT_CUDA_ARCHITECTURES}
+             CUDA_ARCHITECTURES "${FINUFFT_CUDA_ARCHITECTURES}"
              CUDA_SEPARABLE_COMPILATION ON
              CUDA_STANDARD 17
              CUDA_STANDARD_REQUIRED ON)
@@ -78,12 +78,11 @@ endif()
 
 set_target_properties(
   cufinufft
-  PROPERTIES CUDA_ARCHITECTURES ${FINUFFT_CUDA_ARCHITECTURES}
+  PROPERTIES CUDA_ARCHITECTURES "${FINUFFT_CUDA_ARCHITECTURES}"
              CUDA_SEPARABLE_COMPILATION ON
              CUDA_STANDARD 17
              CUDA_STANDARD_REQUIRED ON
-             ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}"
-             CUDA_ARCHITECTURES ${FINUFFT_CUDA_ARCHITECTURES})
+             ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}")
 target_compile_features(cufinufft PRIVATE cxx_std_17)
 
 if(WIN32)