title: Install openexr in python doesn't work
body: <p>I have successfully installed <em>openexr</em> using <code>pip install openexr</code> on my mac, but the same command fails on Ubuntu:</p>
  
  <pre><code>OpenEXR.cpp:9:22: fatal error: ImathBox.h: No such file or directory
    compilation terminated.
    error: command 'x86_64-linux-gnu-gcc' failed with exit status 1
  
    ----------------------------------------
    Failed building wheel for openex
  </code></pre>
  
  <p>I tried using <code>apt-get install openexr</code> which seems like to install without an error but then when I try to <code>import OpenEXR</code> in python, it doesn't work. </p>
  
  <p>Does anyone know why?</p>