Fix StackSetupShim.hs for GHC < 8.0

718ee02 used a feature (the CPP macro `MIN_VERSION_Cabal`) which was not introduced until GHC 8.0. This tests that it is defined before using it. If it is not defined, it assumes Cabal < 3.8.1.0.

Author: mpilgrem

src/setup-shim/StackSetupShim.hs

@@ -2,11 +2,15 @@
 {-# LANGUAGE PackageImports #-}
 module StackSetupShim where
 import Main
+#if defined(MIN_VERSION_Cabal)
 #if MIN_VERSION_Cabal(3,8,1)
 import Distribution.PackageDescription (PackageDescription, emptyHookedBuildInfo)
 #else
 import "Cabal" Distribution.PackageDescription (PackageDescription, emptyHookedBuildInfo)
 #endif
+#else
+import Distribution.PackageDescription (PackageDescription, emptyHookedBuildInfo)
+#endif
 import Distribution.Simple
 import Distribution.Simple.Build
 import Distribution.Simple.Setup (ReplFlags, fromFlag, replDistPref, replVerbosity)