Fix yaml-cpp-config.cmake.in

Author: Levi-Armstrong

yaml-cpp-config.cmake.in

@@ -19,8 +19,11 @@ include("${CMAKE_CURRENT_LIST_DIR}/yaml-cpp-targets.cmake")
 # These are IMPORTED targets created by yaml-cpp-targets.cmake
 set(YAML_CPP_LIBRARIES "@EXPORT_TARGETS@")
 
-add_library(yaml-cpp INTERFACE IMPORTED)
-target_link_libraries(yaml-cpp INTERFACE yaml-cpp::yaml-cpp)
+if(NOT TARGET yaml-cpp)
+  add_library(yaml-cpp INTERFACE IMPORTED) 
+  target_link_libraries(yaml-cpp INTERFACE yaml-cpp::yaml-cpp) 
+endif()
+
 if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.17)
   set_target_properties(yaml-cpp PROPERTIES 
     DEPRECATION "The target yaml-cpp is deprecated and will be removed in version 0.10.0. Use the yaml-cpp::yaml-cpp target instead."