mpool_zero_alloc
mpool_zero_alloc(memory_pool *pool, size_t size)
return mpool_zero_alloc(mpool_at(level), size, descr);
return mpool_zero_alloc(mpool_at(level), size);
return mpool_zero_alloc(&expr_pool, s, descr);
return mpool_zero_alloc(&expr_pool, size);