1add_custom_command(TARGET targetname
2  COMMENT "Symlinking compile_commands.json for LSP convenience"
3  DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/compile_commands.json"
4  POST_BUILD 
5  COMMAND ${CMAKE_COMMAND} -E create_symlink 
6    "${CMAKE_CURRENT_BINARY_DIR}/compile_commands.json"
7    "${PROJECT_SOURCE_DIR}/compile_commands.json")