Unbreak -DX when not invoking executable as "xdos"
"Unknown debug-msg mask: X"

It is bogus putting register_debug_class later than config_init()
as usage() won't show -DX - we're not going to reuse letters anyway
(we have lots of spare letters and it would be confusing otherwise).

I would say the same about "./src/plugin/translate/translate.c:     register_debug_class('u', 0, "Unicode translation");"
but unfortunately but it's called earlier than even dyndeb.c:init() so not sure if safe to move into there as well.


git-svn-id: https://dosemu.svn.sourceforge.net/svnroot/dosemu/trunk@1148 7758b857-130e-0410-ab9c-d8735a528d18