title: CMake-gui toggle visibility of variable
body: <p>I have a CMake setup where the accessibilty of one variable will depend whether another one is set or not. Small snippet:</p>
  
  <pre><code>option(build-compiler "Build the Nap Compiler" ON)
  set(include_interrupt_dirs CACHE INTERNAL "interrupts/intr_4" FORCE)
  
  if(build-compiler)
      option(enable-runtime-compilation 
             "Build in the runtime code compilation link in intr_2 &amp; intr_3)" ON)
      if(enable-runtime-compilation)
          list(APPEND include_interrupt_dirs "interrupts/intr_2" "interrupts/intr_3" )
      endif()
  endif()
  </code></pre>
  
  <p>I use cmake-gui for configuring the project, and what I would like to achieve is:</p>
  
  <ol>
  <li>if the user selects the <code>build-compiler</code> the <code>enable-runtime-compilation</code> should also be presented. This part is done.</li>
  <li>if the user deselects the <code>build-compiler</code> the <code>enable-runtime-compilation</code> should be <strong>hidden</strong> from the GUI. This is not working.</li>
  </ol>
  
  <p>Do you have any idea how to make it work?</p>