ghc package installation depends on /home/user/.ghc data

Hi,

when trying to get EclipseFP running I encountered some strange compile errors and decided to purge the ghc package and reinstall it afterwards using

sudo apt-get purge g++-4.6 libbsd-dev libffi-dev libgmp-dev libstdc++6-4.6-dev cabal-install ghc ghc-prof libstdc++-4.8-dev
sudo apt-get install ghc

This resulted in a lot of error messages like the following:

Setting up ghc (7.6.3-4) ...
update-alternatives: using /usr/bin/runghc to provide /usr/bin/runhaskell (runhaskell) in auto mode
update-alternatives: using /usr/bin/ghc to provide /usr/bin/haskell-compiler (haskell-compiler) in auto mode
There are problems in package pandoc-types-1.10:
  Warning: library-dirs: /home/user/.cabal/lib/pandoc-types-1.10/ghc-7.6.3 doesn't exist or isn't a directory
  import-dirs: /home/user/.cabal/lib/pandoc-types-1.10/ghc-7.6.3 doesn't exist or isn't a directory
  file Text/Pandoc/Definition.hi is missing
  file Text/Pandoc/Generic.hi is missing
  file Text/Pandoc/Builder.hi is missing
  cannot find libHSpandoc-types-1.10.a on library path
There are problems in package hs-bibutils-5.0:
  Warning: library-dirs: /home/user/.cabal/lib/hs-bibutils-5.0/ghc-7.6.3 doesn't exist or isn't a directory
  import-dirs: /home/user/.cabal/lib/hs-bibutils-5.0/ghc-7.6.3 doesn't exist or isn't a directory
  file Text/Bibutils.hi is missing
  cannot find libHShs-bibutils-5.0.a on library path
[...]
The following packages are broken, either because they have a problem
listed above, or because they depend on a broken package.
pandoc-types-1.10
hs-bibutils-5.0
[...]

`/home/user` is the home directory of the user running the `sudo apt-get` command. I had removed the .cabal directory before in an attempt to remedy my previous compile problems but appearantly there where still references to it in the `/home/user/.ghc` directory. For example `/home/user/.ghc/x86_64-linux-7.6.3/package.conf.d/ghc-paths-0.1.0.9-33cf158d45e15d2ea66fe4694a916f3a.conf` contains:
import-dirs: /home/user/.cabal/lib/ghc-paths-0.1.0.9/ghc-7.6.3
library-dirs: /home/user/.cabal/lib/ghc-paths-0.1.0.9/ghc-7.6.3

Once I removed the .ghc directory or ran the command in a root shell (`sudo su`) the installation of the package ran through without any errors. So appearantly the package installation uses some of the local data of the user performing the installation command.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: ghc 7.6.3-4
ProcVersionSignature: Ubuntu 3.11.0-14.21-generic 3.11.7
Uname: Linux 3.11.0-14-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
Date: Sun Dec 15 22:57:13 2013
InstallationDate: Installed on 2013-04-18 (241 days ago)
InstallationMedia: Ubuntu-GNOME 13.04 "Raring Ringtail" - Alpha amd64 (20130402.1)
MarkForUpload: True
SourcePackage: ghc
UpgradeStatus: Upgraded to saucy on 2013-10-29 (47 days ago)