Changes to ghc(4)

Changes to ghc:
commit 1a7709ef9b25175566bc040a34b3d479ea8566ed
Author: Simon Peyton Jones <simonpj@microsoft.com>
Date:   Sun Mar 23 18:46:22 2014 +0000

    Trac #8831 is fixed

commit 7973bfb87fdbe6e980e64ed5d7b2a90a469effd4
Author: Simon Peyton Jones <simonpj@microsoft.com>
Date:   Sun Mar 23 18:44:43 2014 +0000

    Test Trac #8893

commit 28e8d878b63d06824001ac3a631254679e0f1960
Author: Simon Peyton Jones <simonpj@microsoft.com>
Date:   Sat Mar 22 23:18:14 2014 +0000

    Simplify handling of the interactive package; fixes Trac #8831

    This patch is really a fix to the big commint
       73c08ab10e4077e18e459a1325996bff110360c3
       Re-work the naming story for the GHCi prompt (Trac #8649)
    which introduced the 'interactive' package
    See Note [The interactive package] in HscTypes

    The original commit set both
      (a) The tcg_mod field of TcGblEnv to 'interactive:Ghci4' (say)
      (b) The thisPackage field of DynFlags to 'interactive'

    But the second step interacts badly with linking.  :loaded modules are
    in the package set by 'thisPackage' (usually 'main'); if you change
    that, then we try to link package 'main', but can't find it, and
    that is what happened in #8831.

    The fix was simple: do (a) but not (b).

    I changed Note [The interactive package] in HscTypes to describe this.

commit ffed708c30f2d1d4b4c5cd08d9c19aeb0bb623ec
Author: Simon Peyton Jones <simonpj@microsoft.com>
Date:   Sat Mar 22 23:11:10 2014 +0000

    Apply the kind subst to the (kinds of the) quanitifed tyvars in deriveTyData

    I've elaboated Note [Unify kinds in deriving] to explain
    what is going on here.

    The change fixes Trac #8893.