title: node-gyp rebuild fails while installing node modules
body: <p>I am trying to install node_xslt module in node 0.12 but it is failing. I have python version 2.7 and node-gyp version 2.0.2. </p>
  
  <p>Here is the error stack-</p>
  
  <pre><code>&gt; node_xslt@0.1.9 preinstall /home/ritesh/Ritesh/projects/applane1/node_modules/node_xslt
  &gt; node-gyp rebuild
  
  /bin/sh: 1: xml2-config: not found
  gyp: Call to 'xml2-config --cflags' returned exit status 127. while trying to load binding.gyp
  gyp ERR! configure error 
  gyp ERR! stack Error: `gyp` failed with exit code: 1
  gyp ERR! stack     at ChildProcess.onCpExit (/usr/local/lib/node_modules/npm/node_modules/node-gyp/lib/configure.js:343:16)
  gyp ERR! stack     at ChildProcess.emit (events.js:110:17)
  gyp ERR! stack     at Process.ChildProcess._handle.onexit (child_process.js:1074:12)
  gyp ERR! System Linux 3.13.0-32-generic
  gyp ERR! command "node" "/usr/local/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
  gyp ERR! cwd /home/ritesh/Ritesh/projects/applane1/node_modules/node_xslt
  gyp ERR! node -v v0.12.4
  gyp ERR! node-gyp -v v1.0.3
  gyp ERR! not ok 
  npm ERR! Linux 3.13.0-32-generic
  npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "install" "node_xslt"
  npm ERR! node v0.12.4
  npm ERR! npm  v2.10.1
  npm ERR! code ELIFECYCLE
  
  npm ERR! node_xslt@0.1.9 preinstall: `node-gyp rebuild`
  npm ERR! Exit status 1
  npm ERR! 
  npm ERR! Failed at the node_xslt@0.1.9 preinstall script 'node-gyp rebuild'.
  npm ERR! This is most likely a problem with the node_xslt package,
  npm ERR! not with npm itself.
  npm ERR! Tell the author that this fails on your system:
  npm ERR!     node-gyp rebuild
  npm ERR! You can get their info via:
  npm ERR!     npm owner ls node_xslt
  npm ERR! There is likely additional logging output above.
  
  npm ERR! Please include the following file with any support request:
  npm ERR!     /node_modules/npm-debug.log
  </code></pre>
  
  <p>This error comes while installing other modules as well i.e. xslt4node.</p>