[PATCH v3 03/10] reg: Add system error printing function

[Jonathan Vollebregt]

> This seems like a step backwards to me. It would be much better to add the required functionality -- e.g. FormatMessage() -- and fix reg.exe printf-style functions in one go.

I'd still have to use reg_print_error as is because it's there to get 
the error string from standard error codes like ERROR_INVALID_DATA not 
to actually format the output string (FORMAT_MESSAGE_FROM_SYSTEM vs 
FORMAT_MESSAGE_FROM_STRING)

I like splitting the writing part into output_write (That might come in 
handy for printing long strings in reg query if we can't find a way to 
make reg_printfW variable size)

Giving reg_message extra arguments is a good idea, but I'm not sure if 
we're supposed to have format specifiers in LoadString resources.

I'm not sure whether having output_vprintf is really an advantage over 
just calling reg_printf since it uses different format specifiers than 
printf and basically does the same thing (Minus the variable size issue 
of course)