title: CMake IF with multiple conditions
body: <p>How to make if function with multiple conditions? I know CMake support if with 2 conditions, but how to make more than 3?
  I need something like this:</p>
  <pre><code>if(WIN32 OR APPLE OR IOS)
      set(LIBS)
  endif()
  </code></pre>
  <p>Thanks</p>