title: CMake variable names case sensitive?
body: <p>How does CMake treat variable names? Are they case sensitive?</p>
  
  <p>If I use <code>FindFoo.cmake</code> with</p>
  
  <pre><code>find_package(Foo)
  </code></pre>
  
  <p>can I use <code>FOO_FOUND</code>, <code>Foo_FOUND</code> and <code>foo_FOUND</code>?</p>