The isFree attribute is not (or bad) used in ralloc.c in the STM8 port. Thus the function isFreeSTM8() always return FALSE and the stack variables are not recycled when they could be.
This patch removes completely the isFree attribute, and removes a memory leak since the stacks allocation were not freed.
This provides a big stack usage improvement in case of long and complex functions.
The regression tests have been passed at 100%