title: CMake: How to add dependency on linker script for executable
body: <p>I have a CMake script where the final executable is linked with my own linker script:</p>
  
  <pre><code>cmake_minimum_required(VERSION 3.1)
  
  project(test_app)
  
  set(LINKER_SCRIPT "linker.ld")
  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -T ${LINKER_SCRIPT}")
  
  add_executable(${PROJECT_NAME}.elf
      main.cpp
      startup.cpp
  )
  </code></pre>
  
  <p>How do I make an executable dependent also on the linker script file (trigger linking if <code>linker.ld</code> was changed)?</p>