[Agda] Agda fails to build on GHC 7.8

[Jan Stolarek]

It looks like Agda does not build with GHC 7.8 (tested on RC2):

- stable version on Hackage fails with:

cabal: Could not resolve dependencies:
trying: Agda-2.3.2.2 (user goal)
next goal: base (dependency of Agda-2.3.2.2)
rejecting: base-4.7.0.0/installed-eb2... (conflict: Agda => base>=4.2 && <4.7)
rejecting: base-4.6.0.1, 4.6.0.0, 4.5.1.0, 4.5.0.0, 4.4.1.0, 4.4.0.0, 4.3.1.0,
4.3.0.0, 4.2.0.2, 4.2.0.1, 4.2.0.0, 4.1.0.0, 4.0.0.0, 3.0.3.2, 3.0.3.1 (global
constraint requires installed instance)
Dependency tree exhaustively searched.

- development version fails because it tries to install template-haskell-2.8.0.0 which does not 
work with GHC 7.8:

Failed to install template-haskell-2.8.0.0
Last 10 lines of the build log ( /home/killy/.cabal/logs/template-haskell-2.8.0.0.log ):
    Couldn't match expected type ‘Bool’ with actual type ‘Int#’
    In the expression: u1 ==# u2
    In a stmt of a pattern guard for
                   an equation for ‘compare’:
      u1 ==# u2
    In an equation for ‘compare’:
        (NameL u1) `compare` (NameL u2)
          | u1 <# u2 = LT
          | u1 ==# u2 = EQ
          | otherwise = GT

Janek