REL_BLOCK
pool->rels = solv_extend_resize(0, 1, sizeof(Reldep), REL_BLOCK);
pool->rels = solv_extend(pool->rels, id, 1, sizeof(Reldep), REL_BLOCK);
pool->rels = solv_extend_resize(pool->rels, pool->nrels, sizeof(Reldep), REL_BLOCK);
pool->relhashmask = hashmask = mkmask(pool->nrels + REL_BLOCK);