Enable OSD windows output support

[tempt187]

It appears MAME output via the mame.ini "output console/network/windows" only console and network are outputting data.

If you run a game with the mame.ini set to "output windows" the error comes up as:

[libretro WARN] Value windows not supported for option output - falling back to auto

Could we get a windows compiled core with this feature enabled?

Seems like the code is there at in the win32_output.cpp but it's just not enabled for the Win64 version?

[sonninnos]

This libretro port does not have any win32 osd modules, since this is not a win32 build.. Everything else uses retro modules, except output seems to be barebones only with no specific retro one.