Applyed changes from discussion '[Canfestival-devel] some minor CanFestival build suggestions', https://sourceforge.net/mailarchive/message.php?msg_id=28397766

/* 
Define the i/o port global symbol 
*/

.globl _io_ports
_io_ports=0x0000	
	
/* 
0x0000 is the default mapping at reset. (it is 0x1000 for 68hc11)
*/