Support "unsigned short".

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@2357 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/dl/lib/dl/struct.rb

@@ -43,6 +43,10 @@ module DL
 	    ].join("\n")
 	  }
 	end
+
+	def to_ptr
+	  return @ptr
+	end
       end
 
       class Struct