pool_id2solvable
Solvable *solvable = pool_id2solvable(pool, solvableId);
s = pool_id2solvable(pool, repo_add_solvable(repo));
s = pool_id2solvable(pool, extendstart);
s = pool_id2solvable(pool, repo_add_solvable_block(repo, numsolv));