Import hs-Cabal-1.16.0.3 as wip/hs-Cabal.

The Haskell Common Architecture for Building Applications and
Libraries: a framework defining a common interface for authors to more
easily build their Haskell applications in a portable way.

The Haskell Cabal is part of a larger infrastructure for distributing,
organizing, and cataloging Haskell libraries and tools.
+hs-Cabal
Upstream update to cabal-install-1.16.0.2
Upstream update to hscolour-1.20.3
Restore release flag.
* Fix build.
* Update TODO.
buildlink3.mk: update BUILDLINK_API_DEPENDS