title: CMake IF(something OR something else)
body: <p>Does the CMake <code>IF</code> statement have an <code>OR</code> option as well?  Something like: <code>IF (NOT this OR that) ... ENDIF</code>?</p>
  
  <p>I have the line <code>if (NOT ${TARGET_PLATFORM} STREQUAL "test")</code>, which removes certain build files from the project.  I want to add a second Target platform option, "my_board", which needs to remove those same build files.  I tried adding an <code>elseif(NOT ${TARGET_PLATFORM} STREQUAL "my_board")</code> following the first <code>IF</code>, but that was not successful.</p>
  
  <p>Is what I am trying to do possible with CMake, and if so, what is the proper syntax?</p>
  
  <p>Thanks</p>