squash! [CMake] Make nlohmann_json config target-based.

+ RDF

Author: hageboeck

tree/dataframe/CMakeLists.txt

@@ -152,10 +152,6 @@ if(MSVC)
   target_compile_definitions(ROOTDataFrame PRIVATE _USE_MATH_DEFINES)
 endif()
 
-if(builtin_nlohmannjson)
-  target_include_directories(ROOTDataFrame PRIVATE ${CMAKE_SOURCE_DIR}/builtins)
-else()
-  target_link_libraries(ROOTDataFrame PUBLIC nlohmann_json::nlohmann_json)
-endif()
+target_link_libraries(ROOTDataFrame PUBLIC nlohmann_json::nlohmann_json)
 
 ROOT_ADD_TEST_SUBDIRECTORY(test)