title: Installing gcc49 with Homebrew
body: <p>I'm trying to get Homebrew to install <code>gcc49</code> (GCC 4.9). Specifically, I'm installing using the command,</p>
  
  <pre><code>brew install homebrew/versions/gcc49
  </code></pre>
  
  <p>However, doing this normally, I get an error saying that I'm missing <code>gmp4</code>. This is where it gets weird.</p>
  
  <p>If I then do <code>brew install homebrew/versions/gmp4</code>, I'm informed once again that <code>gmp4</code> is missing. The library doesn't install. The exact same thing happens for a few other required libraries. Right now, rather than fixing this strange behaviour, I'm trying to run</p>
  
  <pre><code>brew install homebrew/versions/gcc48 --with homebrew/versions/gmp4 --with homebrew/versions/libmpc08 --with homebrew/versions/mpfr2 --with homebrew/versions/cloog018 --with homebrew/versions/isl011
  </code></pre>
  
  <p>... Which results in</p>
  
  <pre><code>==&gt; Installing dependencies for gcc48: gmp4, mpfr2, libmpc08, isl011, cloog018
  ==&gt; Installing gcc48 dependency: gmp4
  ==&gt; Downloading ftp://ftp.gmplib.org/pub/gmp/gmp-5.1.3.tar.bz2
  ######################################################################## 100.0%
  ==&gt; Patching
  patching file gmp-h.in
  ==&gt; ./configure --prefix=/usr/local/Cellar/gmp/5.1.3 --enable-cxx
  ==&gt; make
  ==&gt; make check
  ==&gt; make install
  Error: Empty installation
  </code></pre>
  
  <p>It's that last line that really confuses me. I've never seen that returned by any software I've tried to install - what's going on, and how can I fix it?</p>
  
  <p>Interestingly enough, when I try this on my desktop, which has the same Homebrew version, GCC 4.9 installs without a problem by simply running <code>brew install gcc49</code>, without even having to go through <code>homebrew/versions</code>.</p>