The -X option in pg_dump was supposed to be a workaround for the lack of

portable long options.  But we have had portable long options for a long
time now, so this is obsolete.  Now people have added options which *only*
work with -X but not as regular long option, so I'm putting a stop to this:
-X is deprecated; it still works, but it has been removed from the
documentation, and please don't add more of them.