xcb_proto: Pass / as DESTDIR

This works around py-compile complaining about an empty DESTDIR.

Note however some python files end up in non-packaged/... FIXME

x11-proto/xcb_proto/xcb_proto-1.6.recipe

@@ -46,5 +46,5 @@ BUILD()
 
 INSTALL()
 {
-	make install
+	make install DESTDIR=/
 }