STACK_LENGTH     3891 gc.c           # define STACK_LENGTH  (size_t)(STACK_START - STACK_END)
STACK_LENGTH     3893 gc.c           # define STACK_LENGTH  (size_t)(STACK_END - STACK_START + 1)
STACK_LENGTH     3895 gc.c           # define STACK_LENGTH  ((STACK_END < STACK_START) ? (size_t)(STACK_START - STACK_END) \