map_alloc
int map_alloc;
map = map_alloc(gpt, block, sectors, alignsecs);
map = map_alloc(gpt, block, sectors, 0);
n->map_alloc = alloc;
m->map_alloc = alloc;
m->map_alloc = 0;
if (m->map_alloc)
int map_alloc;
struct map *map_alloc(struct gpt *, off_t, off_t, off_t);