apic_find_bus_id
if (((busid = apic_find_bus_id(bustype)) != -1) &&
int apic_find_bus_id(int bustype);
extern int apic_find_bus_id(int bustype);
if (((busid = apic_find_bus_id(bustype)) != -1) &&
extern int apic_find_bus_id(int bustype);
if (((busid = apic_find_bus_id(bustype)) != -1) &&
extern int apic_find_bus_id(int bustype);