merges r24408 and r24409 from trunk into ruby_1_9_1.

--
* ruby.c (rb_stdio_set_default_encoding): declared.
--
* io.c (rb_stdio_set_default_encoding): prototyped.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@24471 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ruby.c

@@ -1188,6 +1188,8 @@ rb_f_chomp(argc, argv)
     return str;
 }
 
+void rb_stdio_set_default_encoding(void);
+
 static VALUE
 process_options(VALUE arg)
 {