New formula: reattach-to-user-namespace

A small utility that can be used to fix broken OSX clipboard integration
in a variety of tools, most notably tmux and screen.

Closes Homebrew/homebrew#8016.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Formula/reattach-to-user-namespace.rb

@@ -0,0 +1,38 @@
+require 'formula'
+
+class ReattachToUserNamespace < Formula
+  head 'https://github.com/ChrisJohnsen/tmux-MacOSX-pasteboard.git'
+  homepage 'https://github.com/ChrisJohnsen/tmux-MacOSX-pasteboard'
+  url 'https://github.com/ChrisJohnsen/tmux-MacOSX-pasteboard.git', :tag => 'dadea0aa48259c704d0b412b9588de2f5623e323'
+  version 'dadea0'
+
+  def options
+    [
+      ['--wrap-pbcopy-and-pbpaste', 'Include wrappers for pbcopy/pbpaste that shim in this fix'],
+      ['--wrap-launchctl', 'Include wrapper for launchctl with this fix']
+    ]
+  end
+
+  def install
+    system "make"
+    bin.install "reattach-to-user-namespace"
+    wrap_pbpasteboard_commands if ARGV.include? '--wrap-pbcopy-and-pbpaste'
+    wrap_launchctl if ARGV.include? '--wrap-launchctl'
+  end
+
+  def wrap_pbpasteboard_commands
+    make_executable_with_content('pbcopy', 'cat - | reattach-to-user-namespace /usr/bin/pbcopy')
+    make_executable_with_content('pbpaste', 'reattach-to-user-namespace /usr/bin/pbpaste')
+  end
+
+  def wrap_launchctl
+    make_executable_with_content('launchctl', 'reattach-to-user-namespace /bin/launchctl "$@"')
+  end
+
+  def make_executable_with_content(executable_name, content_lines)
+    executable = bin.join(executable_name)
+    content = [*content_lines].unshift("#!/bin/sh").join("\n")
+    executable.write(content)
+    executable.chmod(0755)
+  end
+end