/* A place for image types to store additional data. The member
data.lisp_val is marked during GC, so it's safe to store Lisp data
there. Image types should free this data when their `free'
/* A place for image types to store additional data. The member
data.lisp_val is marked during GC, so it's safe to store Lisp data
there. Image types should free this data when their `free'