title: Warning message when opening RStudio or the R console
body: <p>recently I installed Microsoft R Open 3.3.1 on my MacBook Pro (El Capitan 10.11.6). When I open RStudio or I use the R console I get this warning message:</p>
  
  <pre><code>Warning message:
  In doTryCatch(return(expr), name, parentenv, handler) :
    unable to load shared object '/Library/Frameworks/R.framework/Resources/modules//R_X11.so':
    dlopen(/Library/Frameworks/R.framework/Resources/modules//R_X11.so, 6): Symbol not found: _CGBitmapContextCreate
    Referenced from: /Library/Frameworks/R.framework/Resources/modules//R_X11.so
    Expected in: flat namespace
   in /Library/Frameworks/R.framework/Resources/modules//R_X11.so
  </code></pre>
  
  <p>Do you know a way to prevent the printing of the message (or solve the issue)?</p>
  
  <p>Thanks!</p>