s3cmd: use setuptools to install

Setuptools will rewrite the shebang for us, avoiding issues like Homebrew/homebrew#36128.

Closes Homebrew/homebrew#36174. Fixes Homebrew/homebrew#36128.

Formula/s3cmd.rb

@@ -1,11 +1,11 @@
-require 'formula'
-
 class S3cmd < Formula
   homepage 'http://s3tools.org/s3cmd'
   url 'https://downloads.sourceforge.net/project/s3tools/s3cmd/1.5.0/s3cmd-1.5.0.tar.gz'
   sha1 '53ebc485329cb15cad8f61ca0c8c2d06563ee2f3'
   head 'https://github.com/s3tools/s3cmd.git'
 
+  depends_on :python if MacOS.version <= :snow_leopard
+
   bottle do
     cellar :any
     sha1 "254a78674d86587e18419099e20059c61b5a257a" => :yosemite
@@ -13,9 +13,27 @@ class S3cmd < Formula
     sha1 "ec0dd6f3298c8b8aa5dab60e395d7c013a6747c9" => :mountain_lion
   end
 
+  resource "six" do
+    url "https://pypi.python.org/packages/source/s/six/six-1.9.0.tar.gz"
+    sha1 "d168e6d01f0900875c6ecebc97da72d0fda31129"
+  end
+
+  resource "python-dateutil" do
+    url "https://pypi.python.org/packages/source/p/python-dateutil/python-dateutil-2.4.0.tar.gz"
+    sha1 "159081a4c5b3602ab440a7db305f987c00ee8c6d"
+  end
+
   def install
-    libexec.install 's3cmd', 'S3'
-    man1.install 's3cmd.1'
-    bin.install_symlink libexec+'s3cmd'
+    ENV.prepend_create_path "PYTHONPATH", libexec/"vendor/lib/python2.7/site-packages"
+    resources.each do |r|
+      r.stage { system "python", *Language::Python.setup_install_args(libexec/"vendor") }
+    end
+
+    ENV.prepend_create_path "PYTHONPATH", libexec/"lib/python2.7/site-packages"
+    system "python", *Language::Python.setup_install_args(libexec)
+
+    bin.install Dir[libexec/"bin/*"]
+    bin.env_script_all_files(libexec/"bin", :PYTHONPATH => ENV["PYTHONPATH"])
+    man1.install Dir[libexec/"share/man/man1/*"]
   end
 end