title: Caret install package, had non-zero exit in Ubuntu 14.04 LTS 32 bit
body: <p>When trying to install the caret package on Ubuntu 14.04 LTS 32 bit I received the following warnings</p>
  
  <pre><code>The downloaded source packages are in
  
  ‘/tmp/RtmpnrWGAe/downloaded_packages’ 
  
  
  
   Warning messages:  
  1: In install.packages("caret") :
    installation of package ‘nloptr’ had non-zero exit status   
  2: In install.packages("caret") :
    installation of package ‘lme4’ had non-zero exit status  
  3: In install.packages("caret") :
    installation of package ‘pbkrtest’ had non-zero exit status  
  4: In install.packages("caret") :
    installation of package ‘BradleyTerry2’ had non-zero exit status
  5: In install.packages("caret") :
    installation of package ‘car’ had non-zero exit status  
  6: In install.packages("caret") :
    installation of package ‘caret’ had non-zero exit status  
  </code></pre>