Passing --hoogle to haddock when building base

[Claus Reinke]

> I'm revisiting Hoogle development and the base library is the one
> sticking point before I make a new Hoogle release. 

While you're revisiting Hoogle, might you be able to
work from .haddock and .hi files (via haddock API and
GHC API/ghci), instead of from sources, making Hoogle
independent of/separate from Haddock's frontend?

See also: 

    Push/improve Haddock API and .haddock files usage
    http://trac.haskell.org/haddock/ticket/157

The hoogle file looks like Haddock docs (which should
be in .haddock?, available via Haddock API) plus types 
(which should be avaible from ghci's :browse, or via 
the GHC API).

I'm having a similar problem for indices needed for
haskellmode for Vim, and I doubt we can extend
Haddock for every tool, nor distribute separate files
for every tool. I don't want to talk people out of
supporting Hoogle, since the support is already in,
but I would like a more general solution.

Claus