This change removes duplicated entries from MASTER_SITES and DISTFILES
variables. Now the MASTER_SITES variable will contain single Hackage URL without
any group for the simplest case and with :_cabal_mk_hackage group in nodefault
case.
This change opens a path to using non-Hackage Cabal repositories
(needed for Cardano) and pulling in .cabal revisions without using patches.
Unfortunately, this change results in a large churn in Haskell ports distinfos.
To make this churn less useless, refresh all Haskell dependencies in all ports.
2fca7097b9