fixing the Storable instance.

Author: kazu-yamamoto

Network/Socket/Unix.hsc

@@ -82,8 +82,8 @@ getPeerCred s = do
 newtype PeerCred = PeerCred (CUInt, CUInt, CUInt)
 instance Storable PeerCred where
     sizeOf _ = (#const sizeof(struct ucred))
-    alignment _ =  (#const sizeof(int))
-    poke = undefined
+    alignment _ = alignment (undefined :: CInt)
+    poke _ _ = return ()
     peek p = do
         pid <- (#peek struct ucred, pid) p
         uid <- (#peek struct ucred, uid) p