Restore the original build script relying on the global package database
Restore the original build script relying on the global package database

See #435, #430

sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,snowleopard/hadrian,snowleopard/shaking-up-ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,bgamari/shaking-up-ghc,sdiehl/ghc