change parameter type to avoid unnecessary copies of string.
change stack depth from 65536<<4 to 16+(65536<<2).
now you could know stack overflow when it happens
a gc bug which causes fatal error.
add member value collect to make sure that nasal_val is not collected repeatedly.
use builtin_alloc in builtin function to avoid incorrect collection of value in use(gc_alloc).
change free_list to free_list[vm_type_size] to avoid too many calls of new/delete(but seems useless?)
but the most important thing is fixing this bug.
Li Haokun
Valk Richard Li