title: installation of package ‘RCurl’ had non-zero exit status
body: <p>I am trying to install RCurl on OS X 10.12.6 but get the following error:</p>
  
  <pre><code>Error: package or namespace load failed for ‘RCurl’ in dyn.load(file, DLLpath = DLLpath, ...):
   unable to load shared object '/Users/nick/Library/R/3.4/library/RCurl/libs/RCurl.so':
    dlopen(/Users/nick/Library/R/3.4/library/RCurl/libs/RCurl.so, 6): Library not loaded: @rpath/libcurl.4.dylib
    Referenced from: /Users/nick/Library/R/3.4/library/RCurl/libs/RCurl.so
    Reason: image not found
  Error: loading failed
  Execution halted
  ERROR: loading failed
  * removing ‘/Users/nick/Library/R/3.4/library/RCurl’
  
  The downloaded source packages are in
      ‘/private/var/folders/hx/9xx9fwq91t95k45dzlmzxfy40000gp/T/Rtmp14zSi1/downloaded_packages’
  Warning message:
  In install.packages("RCurl") :
    installation of package ‘RCurl’ had non-zero exit status
  </code></pre>
  
  <p>This error has been discussed a bit already, but the solutions are all specific to linux and I don't think they are relevant to OS X. I did try installing the homebrew version of <code>curl</code> but that didn't help.</p>
  
  <p>Any ideas? I think that more debugging information would be helpful, but I'm not sure what else to provide. </p>
  
  <p>Thanks in advance!
  Nick</p>