No, of course not.. That pluging would not even compile, if you try to compile it, compilation is failed because "vdr is not compiled with subtitle use-flag"
What is a "subtitle use-flag"? VDR is pretty straight forward to me... Apply whatever patches you like -> compile -> enjoy. I don't set any special flags or modify things like Make.config/Makefile except for adding 'ccache gcc'. No flags or whatever that I know of.