delegate.rb: get rid of global function interference

* lib/delegate.rb (Delegator#send): override to get rid of global function interference.
  [Fixes GH-449]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43682 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/delegate.rb

@@ -74,6 +74,7 @@ class Delegator < BasicObject
       $@.delete_if {|t| %r"\A#{Regexp.quote(__FILE__)}:#{__LINE__-2}:"o =~ t} if $@
     end
   end
+  alias send method_missing
 
   #
   # Checks for a method provided by this the delegate object by forwarding the