fix CMakeLists

CMakeLists.txt

@@ -42,6 +42,12 @@ if(NOT $ENV{AIDGE_INSTALL} STREQUAL "")
 endif()
 find_package(aidge_core REQUIRED)
 
+# Enable CUDA if backend_cuda is found
+find_package(aidge_backend_cuda)
+
+if(aidge_backend_cuda_FOUND)
+    enable_language(CUDA)
+endif()
 ##############################################
 # Create target and set properties