Drop support of GHC < 7

Author: Bodigrim

zlib.cabal

@@ -84,11 +84,7 @@ library
   other-modules:   Codec.Compression.Zlib.Stream,
                    Codec.Compression.Zlib.ByteStringCompat
 
-  if impl(ghc < 7)
-    default-language: Haskell98
-    default-extensions: PatternGuards
-  else
-    default-language: Haskell2010
+  default-language: Haskell2010
 
   other-extensions: CPP, ForeignFunctionInterface, RankNTypes, BangPatterns,
                     DeriveDataTypeable
@@ -97,9 +93,9 @@ library
   if impl(ghc >= 7.6)
     other-extensions: CApiFFI
 
-  build-depends:   base >= 4 && < 4.20,
+  build-depends:   base >= 4.3 && < 4.20,
                    bytestring >= 0.9 && < 0.13
-  if impl(ghc >= 7.0 && < 8.0.3)
+  if impl(ghc < 8.0.3)
     build-depends: ghc-prim
 
   build-tools:     hsc2hs >= 0.67 && < 0.69