Can't install packages with my inplace compiler

[Herbert Valerio Riedel]

Hello Simon,

On 2014-11-04 at 11:55:48 +0100, Simon Peyton Jones wrote:
> When I say
>
> cabal install --with-ghc=/home/simonpj/5builds/HEAD-2/inplace/bin/ghc-stage2
>
> I get this
>
> ghc-stage2: ghc no longer supports single-file style package databases
> (dist/package.conf.inplace) use 'ghc-pkg init' to create the database
> with the correct format.
>
> Now, this is an old build tree, and I could blow it away entirely, but
> maybe there is something else going on.  What should I do?

What does `cabal --version` say? If it doesn't say something like

  $ cabal --version
  cabal-install version 1.21.1.0
  using version 1.21.1.0 of the Cabal library 

you probably need a newer one (in which case you should build the
`cabal` binary from Git, and to make life easier compile `Cabal` and
`cabal-install` with GHC 7.8.x rather than GHC HEAD)

Cheers,
  hvr