Fix various v850 problems

Fix various v850 problems

These fixes fall into a few different buckets.  First c99 doesn't allow a
parameter without a type.  So in cases where the type had previously been an
implicit int, make it an explicit int.  Second, for return values, don't allow
them to be implicit ints either, make them explicit. In a few cases change c89
function definitions to c99 function definitions.   Lastly include <stdlib.h>
in sbrk.c to get the prototype for abort () which we call when we detect a
heap/stack collision.