saves a bit of memory in major GCs
/* Allocate a mark stack if we're doing a major collection.
*/
/* Allocate a mark stack if we're doing a major collection.
*/
+ if (major_gc && oldest_gen->steps[0].mark) {
nat mark_stack_blocks;
mark_stack_blocks = stg_max(MARK_STACK_BLOCKS,
oldest_gen->steps[0].n_old_blocks / 100);
nat mark_stack_blocks;
mark_stack_blocks = stg_max(MARK_STACK_BLOCKS,
oldest_gen->steps[0].n_old_blocks / 100);