Windows: Support long filenames in more (possibly all) of the code

Works around this bug in unix-compat:
https://github.com/jacobstanley/unix-compat/issues/56
getFileStatus and other FilePath using functions in unix-compat do not do
UNC conversion on Windows.

Made Utility.RawFilePath use convertToWindowsNativeNamespace to do the
necessary conversion on windows to support long filenames.

Audited all imports of System.PosixCompat.Files to make sure that no
functions that operate on FilePath were imported from it. Instead, use
the equvilants from Utility.RawFilePath. In particular the
re-export of that module in Common had to be removed, which led to lots
of other changes throughout the code.

The changes to Build.Configure, Build.DesktopFile, and Build.TestConfig
make Utility.Directory not be needed to build setup. And so let it use
Utility.RawFilePath, which depends on unix, which cannot be in
setup-depends.

Sponsored-by: Dartmouth College's Datalad project

Utility/Directory.hs

@@ -16,7 +16,7 @@ module Utility.Directory (
 
 import Control.Monad
 import System.FilePath
-import System.PosixCompat.Files (getSymbolicLinkStatus, isDirectory, isSymbolicLink)
+import System.PosixCompat.Files (isDirectory, isSymbolicLink)
 import Control.Applicative
 import System.IO.Unsafe (unsafeInterleaveIO)
 import Data.Maybe
@@ -25,7 +25,8 @@ import Prelude
 import Utility.SystemDirectory
 import Utility.Exception
 import Utility.Monad
-import Utility.Applicative
+import Utility.FileSystemEncoding
+import qualified Utility.RawFilePath as R
 
 dirCruft :: FilePath -> Bool
 dirCruft "." = True
@@ -65,7 +66,7 @@ dirContentsRecursiveSkipping skipdir followsubdirsymlinks topdir = go [topdir]
 		| otherwise = do
 			let skip = collect (entry:files) dirs' entries
 			let recurse = collect files (entry:dirs') entries
-			ms <- catchMaybeIO $ getSymbolicLinkStatus entry
+			ms <- catchMaybeIO $ R.getSymbolicLinkStatus (toRawFilePath entry)
 			case ms of
 				(Just s) 
 					| isDirectory s -> recurse
@@ -87,9 +88,10 @@ dirTreeRecursiveSkipping skipdir topdir = go [] [topdir]
 		| skipdir (takeFileName dir) = go c dirs
 		| otherwise = unsafeInterleaveIO $ do
 			subdirs <- go []
-				=<< filterM (isDirectory <$$> getSymbolicLinkStatus)
+				=<< filterM isdir
 				=<< catchDefaultIO [] (dirContents dir)
 			go (subdirs++dir:c) dirs
+	isdir p = isDirectory <$> R.getSymbolicLinkStatus (toRawFilePath p)
 
 {- Use with an action that removes something, which may or may not exist.
  -