Re-bundle vendor/listen.

This opens the door for supporting recent versions of listen without
causing undue pain for users of Ruby 1.8.7 on Mac OS X. Listen
versions beyond 1.1 don't support Ruby 1.8.7, but this is installed by
default on many versions of OS X. Widening the version constraint on
listen is also unworkable, since RubyGems will try to select the most
recent version even if it's not compatible with the local Ruby
installation.

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "vendor/listen"]
+	path = vendor/listen
+	url = git://github.com/guard/listen.git

lib/sass/plugin/compiler.rb

@@ -309,7 +309,7 @@ module Sass::Plugin
     private
 
     def create_listener(*args, &block)
-      require 'listen'
+      load_listen!
       Listen::Listener.new(*args, &block)
     end
 
@@ -329,6 +329,43 @@ module Sass::Plugin
       dedupped
     end
 
+    def load_listen!
+      if defined?(gem)
+        begin
+          gem 'listen', '~> 1.1.0'
+          require 'listen'
+        rescue Gem::LoadError
+          dir = Sass::Util.scope("vendor/listen/lib")
+          $LOAD_PATH.unshift dir
+          begin
+            require 'listen'
+          rescue LoadError => e
+            e.message << "\n" <<
+              if File.exists?(scope(".git"))
+                'Run "git submodule update --init" to get the recommended version.'
+              else
+                'Run "gem install listen" to get it.'
+              end
+            raise e
+          end
+        end
+      else
+        begin
+          require 'listen'
+        rescue LoadError => e
+          dir = Sass::Util.scope("vendor/listen/lib")
+          if $LOAD_PATH.include?(dir)
+            raise e unless File.exists?(scope(".git"))
+            e.message << "\n" <<
+              'Run "git submodule update --init" to get the recommended version.'
+          else
+            $LOAD_PATH.unshift dir
+            retry
+          end
+        end
+      end
+    end
+
     def update_stylesheet(filename, css, sourcemap)
       dir = File.dirname(css)
       unless File.exists?(dir)

sass.gemspec

@@ -19,7 +19,6 @@ SASS_GEMSPEC = Gem::Specification.new do |spec|
     END
 
   spec.required_ruby_version = '>= 1.8.7'
-  spec.add_dependency 'listen', '~> 1.1.0'
   spec.add_development_dependency 'yard', '>= 0.5.3'
   spec.add_development_dependency 'maruku', '>= 0.5.9'