Add kprintf for DEBUG(); differentiated from printf()

src/arch/x86/idt.c

@@ -72,6 +72,9 @@ void idt_init()
         // Each vector handler is 16-byte aligned, so <vector_no>*16 = address of that handler
         idt_set_entry(i, vector_0_handler + (i*16), 0);
     }
+
+    idt_set_entry(0x80, syscall_handler, 0);
+
     idt_load(&idt);
     DEBUG("IDT initialized");
 }