debug prints

[Hollis Blanchard]

What would you guys think of something like this:

int grub_debug;
int grub_debug_printf (const char *fmt, ...)
{
        va_list ap;
        int ret;

        if (! grub_debug)
                return;
        va_start (ap, fmt);
        ret = grub_vprintf (fmt, ap);
        va_end (ap);
        return ret;
}

Then grub_debug can be set at runtime to enable debugging messages, 
which could be quite helpful. If we wanted to get fancy, we could turn 
grub_debug into a set of flags (e.g. FILESYSTEM, PARTITION, DISK, 
LINUX, MEMORY) to selectively debug specific systems.

-Hollis