Fix the logic on the CPP hack for CONLIKE

In `Data.ByteString.Builder.Prim.Internal`, the logic to choose whether or not to drop CONLIKE looks borked. I doubt other compilers understand CONLIKE, so this rule should fire whenever "the compiler is not GHC/6.11 or above", rather than "if the compiler is GHC, when the compiler is below GHC/6.11".

I also took the liberty to use `defined()` explicitly for `__GLASGOW_HASKELL__`, for sake of consistency. The only change in logic should be in the imports of `Data.ByteString.Internal`.