core: clean saltine CPP overloads

One year late hah. Thanks Anton!

Author: sorki

hnix-store-core/src/System/Nix/Signature.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-|
 Description : Nix-relevant interfaces to NaCl signatures.
 -}
@@ -16,24 +15,15 @@ import GHC.Generics (Generic)
 import qualified Data.ByteString
 import qualified Data.Coerce
 
---  2021-05-30: NOTE: Please, clean-up these overloads in ~2022
-#if MIN_VERSION_saltine(0,2,0)
 import qualified Crypto.Saltine.Internal.Sign as NaClSizes
-#else
-import qualified Crypto.Saltine.Internal.ByteSizes as NaClSizes
-#endif
 
 -- | A NaCl signature.
 newtype Signature = Signature ByteString
   deriving (Eq, Generic, Ord, Show)
 
 instance IsEncoding Signature where
   decode s
-#if MIN_VERSION_saltine(0,2,0)
     | Data.ByteString.length s == NaClSizes.sign_bytes = Just $ Signature s
-#else
-    | Data.ByteString.length s == NaClSizes.sign = Just $ Signature s
-#endif
     | otherwise = Nothing
   encode = Data.Coerce.coerce