wscript: fix broken build with dvdread+dvdnav in 34e6a26

Didn't know waf actually tried to compile the same files twice.

wscript

@@ -341,6 +341,11 @@ iconv support use --disable-iconv.",
         'func': check_pkg_config('dvdnav',  '>= 4.2.0',
                                  'dvdread', '>= 4.1.0'),
         'default': 'disable',
+    }, {
+        'name': '--dvdread-common',
+        'desc': 'common dvdread code',
+        'deps_any': [ 'dvdread', 'dvdnav' ],
+        'func': check_true,
     }, {
         'name': '--cdda',
         'desc': 'cdda support (libcdio)',

wscript_build.py

@@ -259,10 +259,8 @@ def build(ctx):
         ( "stream/stream_bluray.c",              "libbluray" ),
         ( "stream/stream_cdda.c",                "cdda" ),
         ( "stream/stream_dvb.c",                 "dvbin" ),
-        ( "stream/stream_dvd.c",                 "dvdread" ),
-        ( "stream/stream_dvd.c",                 "dvdnav" ),
-        ( "stream/stream_dvd_common.c",          "dvdread" ),
-        ( "stream/stream_dvd_common.c",          "dvdnav" ),
+        ( "stream/stream_dvd.c",                 "dvdread-common" ),
+        ( "stream/stream_dvd_common.c",          "dvdread-common" ),
         ( "stream/stream_dvdnav.c",              "dvdnav" ),
         ( "stream/stream_edl.c" ),
         ( "stream/stream_file.c" ),