Explicit ordering of `dep` statements is required to resolve dependencies.

[otrho]

Found by @nfurfaro:

In this case,

library std;

dep ops;
dep hash;
dep storage;
dep constants;
dep chain;
dep b512;
dep ecr;

ecr uses b512, so b512 must be declared first.

[otrho]

@nfurfaro Does ecr have a dep b512; of its own? If so then it's definitely a bug, if not I'm not so sure.

[nfurfaro]

@otrho No. In the example, it was just:

library ecr;
use ::b512::*;