*: mass renaming of USE_XXXX to IF_XXXX

and SKIP_XXXX to IF_NOT_XXXX - the second one was especially
badly named. It was not skipping anything!

networking/tunctl.c

@@ -48,9 +48,9 @@ int tunctl_main(int argc UNUSED_PARAM, char **argv)
 	};
 
 	opt_complementary = "=0:t--d:d--t"; // no arguments; t ^ d
-	opts = getopt32(argv, "f:t:d:" USE_FEATURE_TUNCTL_UG("u:g:b"),
+	opts = getopt32(argv, "f:t:d:" IF_FEATURE_TUNCTL_UG("u:g:b"),
 			&opt_device, &opt_name, &opt_name
-			USE_FEATURE_TUNCTL_UG(, &opt_user, &opt_group));
+			IF_FEATURE_TUNCTL_UG(, &opt_user, &opt_group));
 
 	// select device
 	memset(&ifr, 0, sizeof(ifr));