title: Error : Could not find build tools necessary to build
body: <p>I installed Xcode on my Mac, running on the El Capitan version 10.11. I need to get files from a github repository to my workspace in R, so I run the line:</p>
  
  <pre><code>devtools::install_github("Myrepository")
  </code></pre>
  
  <p>And this error appears:</p>
  
  <pre><code>Downloading GitHub repo Myrepository
  from URL https://api.github.com/repos/Myrepository/func/zipball/master
  Erreur : Could not find build tools necessary to build func
  </code></pre>
  
  <p>I thought the problem may come from my gcc command line tools, but when I hit </p>
  
  <pre><code>gcc -v
  </code></pre>
  
  <p>I have it installed:</p>
  
  <pre><code>Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
  Apple LLVM version 7.0.2 (clang-700.1.81)
  Target: x86_64-apple-darwin15.3.0
  Thread model: posix
  </code></pre>
  
  <p>Any ideas?</p>