Properly pass compiler flags detected at configure-timee

Index: Drivers/Screen/AtSpi2/Makefile.in
--- Drivers/Screen/AtSpi2/Makefile.in.orig
+++ Drivers/Screen/AtSpi2/Makefile.in
@@ -28,3 +28,5 @@ include $(SRC_TOP)screen.mk
 screen.$O:
 	$(CC) $(DRIVER_CFLAGS) $(ATSPI2_INCLUDES) $(DBUS_INCLUDES) $(GLIB2_INCLUDES) -c $(SRC_DIR)/screen.c
 
+xsel.$O: $(SRC_TOP)$(PGM_DIR)/xsel.c
+	$(CC) $(DRIVER_CFLAGS) $(X11_INCLUDES) -c $<
