title: Are targets appended?
body: <p>I'm not entirely clear if calling, for instance, <code>target_link_libraries()</code> more than once for the same target will append the target's dependencies. For example, can I add options for the target <code>main</code> as follows?</p>
  
  <pre><code>option(ASSERT "Evaluate assertions" ON)
  
  find_package(MyLib REQUIRED)
  
  add_executable(main main.cpp)
  
  target_link_libraries(main PRIVATE MyLib::MyLib)
  
  if (ASSERT)
      target_link_libraries(main PRIVATE MyLib::enable_assert)
  endif()
  </code></pre>