Homebrew spec

[ened]

It would be help to install djinni conveniently through homebrew. Below is a sample formula.

class Djinni < Formula
  desc "A tool for generating cross-language type declarations and interface bindings"
  homepage "https://github.com/dropbox/djinni"
  head "https://github.com/dropbox/djinni.git"

  def install
    system "make", "djinni"

    inreplace "src/run", '"$base_dir/build"', '# "$base_dir/build"'
    inreplace "src/run", 'exec "$base_dir/target/start"', "exec \"#{prefix}/target/start\""

    prefix.install "src/run"
    prefix.install Dir["src/target/"]    

    bin.install_symlink "#{prefix}/run" => 'djinni'
  end
end