title: npm install canvas dies with "clang: error: no such file or directory: '{{}'"
body: <p>I get this error while installing any node packages that run <code>node-gyp rebuild</code>:</p>
  
  <pre><code>  SOLINK_MODULE(target) Release/canvas-postbuild.node
  clang: error: no such file or directory: '{{}'
  make: *** [Release/canvas-postbuild.node] Error 1
  gyp ERR! build error
  gyp ERR! stack Error: `make` failed with exit code: 2
  gyp ERR! stack     at ChildProcess.onExit (/usr/local/lib/node_modules/npm/node_modules/node-gyp/lib/build.js:267:23)
  gyp ERR! stack     at ChildProcess.emit (events.js:98:17)
  gyp ERR! stack     at Process.ChildProcess._handle.onexit (child_process.js:810:12)
  gyp ERR! System Darwin 14.0.0
  gyp ERR! command "node" "/usr/local/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
  gyp ERR! cwd /Users/arkadiy/node-canvas
  gyp ERR! node -v v0.10.33
  gyp ERR! node-gyp -v v1.0.1
  gyp ERR! not ok
  </code></pre>
  
  <p>I have npm 1.4.28 and all of /usr/local is chowned to me. clang is recent-ish:</p>
  
  <pre><code>Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn)
  Target: x86_64-apple-darwin14.0.0
  Thread model: posix
  </code></pre>
  
  <p>The error is completely ungoogleable (seriously, try it) and I can't even tell where clang is being invoked because the stack trace is only for the callback handler. It seems like a shell substitution/xargs issue almost?</p>