Simplify configure code by relying on ghc >= 6.4
Simplify configure code by relying on ghc >= 6.4

We changed to require ghc >= 6.4 a while ago, this is just a simplification
that was missed at the time.

20080215092628-adfee-a387197a93a3cd68dbb56ef039e2d0bbd290d9a0.gz

dcreager/cabal,dcreager/cabal