Currently, it assumes the package names are identical and this breaks in the
case where integer-gmp is in one package db and integer-simple in another.
This became a problem with the commit: fc2ff6dd7496a33bf68165b28f37f40b7d647418
Instead of following the precedence information, leading to the right choice,
the current code would compare the integer-gmp and integer-simple versions and
pick integer-gmp because it happened to have a greater version, despite having
a lower precedence. See https://github.com/snowleopard/hadrian/issues/702 for
a comprehensive report about the problem.
This effectively un-breaks integer-simple builds with hadrian.