pull in Win32-extras, to be able to get current process id in Windows

Fixed up a number of things that had worked around there not being a way to
get that.

Most notably, transfer info files on windows now include the process id,
since no locking is currently done. This means the file format varies
between windows and unix.

Assistant/Restart.hs

@@ -26,6 +26,9 @@ import Control.Concurrent
 import System.Process (cwd)
 #ifndef mingw32_HOST_OS
 import System.Posix (getProcessID, signalProcess, sigTERM)
+#else
+import System.Win32.Process.Current (getCurrentProcessId)
+import System.Win32.Console (generateConsoleCtrlEvent, cTRL_C_EVENT)
 #endif
 
 {- Before the assistant can be restarted, have to remove our 
@@ -45,14 +48,14 @@ prepRestart = do
  - Wait for browser to update before terminating this process. -}
 postRestart :: URLString -> Assistant ()
 postRestart url = do
-#ifndef mingw32_HOST_OS
 	modifyDaemonStatus_ $ \status -> status { globalRedirUrl = Just url }
 	liftIO . sendNotification . globalRedirNotifier =<< getDaemonStatus
 	void $ liftIO $ forkIO $ do
 		threadDelaySeconds (Seconds 120)
+#ifndef mingw32_HOST_OS
 		signalProcess sigTERM =<< getProcessID
 #else
-	error "TODO windows postRestart"
+		generateConsoleCtrlEvent cTRL_C_EVENT =<< getCurrentProcessId
 #endif
 
 runRestart :: Assistant URLString