Fix path relativity in package db

Stackage/ShakeBuild.hs

@@ -94,29 +94,42 @@ packageTarget pb shakeDir name plan = do
     () <- cmd cwd env "cabal" "copy"
     () <- cmd cwd env "cabal" "register"
     makeFile (targetForPackage shakeDir name)
-    where cwd = Cwd pkgDir
+    where cwd =
-          defaultEnv pwd = [("HASKELL_PACKAGE_SANDBOX",pwd <//> targetForDb shakeDir pb)]
+              Cwd pkgDir
-          opts pwd = ["--package-db=clear"
+          defaultEnv pwd =
+              [ ( "HASKELL_PACKAGE_SANDBOX"
+                , pwd <//>
+                  targetForDb shakeDir pb)]
+          opts pwd =
+              [ "--package-db=clear"
               , "--package-db=global"
               , "--libdir=" ++ pwd <//> pbLibDir pb
               , "--bindir=" ++ pwd <//> pbBinDir pb
               , "--datadir=" ++ pwd <//> pbDataDir pb
               , "--docdir=" ++ pwd <//> pbDocDir pb
               , "--flags=" ++ flags] ++
-                     ["--package-db=" ++ pwd <//> targetForDb shakeDir pb
+              ["--package-db=" ++
-                     |not (pbGlobalInstall pb)]
+               pwd <//>
+               targetForDb shakeDir pb | not (pbGlobalInstall pb)]
           pkgDir =
               shakeDir <//> nameVer
           nameVer =
               display name ++
               "-" ++
               display (ppVersion plan)
-          flags = unwords $ map go $ M.toList (pcFlagOverrides (ppConstraints plan))
+          flags =
+              unwords $
+              map go $
+              M.toList
+                  (pcFlagOverrides
+                       (ppConstraints plan))
             where
-                  go (name', isOn) = concat
+              go (name',isOn) =
-                      [ if isOn then "" else "-"
+                  concat
-                      , T.unpack (unFlagName name')
+                      [ if isOn
-                      ]
+                            then ""
+                            else "-"
+                      , T.unpack (unFlagName name')]
 
 -- | Get the target file for confirming that all packages have been
 -- pre-fetched.