Ruby

• io.c (+ioctl_narg_len) new helper function.
• io.c (rb_io_ctl): don't use ioctl specific length check
  if caller is fcntl.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@33711 b2dd03c8-39d4-4d8f-98ff-823fe69b080e