[MPlayer-dev-eng] Local headers are included over system headers

[Nico Sabbi]

If you configure --without-dvdread-internal and if the dvdread is installed
globally (e.g. in /usr/local/include/dvdread) the code in stream/stream_dvd.h
still includes mplayer's local copy of dvdread headers, contrary to my expectations.
(just include #error EXTERNAL_DVDREAD at the beginning of /usr/local/include/dvdread/dvd_reader.h
and verify) .
The code in stream/stream_dvd.h looks correct to me:

#ifdef USE_DVDREAD_INTERNAL
#include "dvdread/dvd_reader.h"
#include "dvdread/ifo_types.h"
#include "dvdread/ifo_read.h"
#include "dvdread/nav_read.h"
#else
#include <dvdread/dvd_reader.h>
#include <dvdread/ifo_types.h>
#include <dvdread/ifo_read.h>
#include <dvdread/nav_read.h>
#endif

thus the wrong inclusion is probably due to wrong -I flags.
Can someone give it a look, please?