* lib/rake: Import Rake 0.9.2

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@32217 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/rake/multi_task.rb

@@ -0,0 +1,16 @@
+module Rake
+
+  # Same as a regular task, but the immediate prerequisites are done in
+  # parallel using Ruby threads.
+  #
+  class MultiTask < Task
+    private
+    def invoke_prerequisites(args, invocation_chain)
+      threads = @prerequisites.collect { |p|
+        Thread.new(p) { |r| application[r, @scope].invoke_with_call_chain(args, invocation_chain) }
+      }
+      threads.each { |t| t.join }
+    end
+  end
+
+end