Surround stream cache specific code by an appropriate #ifdef; fixes linking

when stream cache is disabled.
noticed by Andrea Palmatè, andrea amigasoft net


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@27210 b3059339-0415-0410-9bf9-f77b7e298cf2

stream/stream.c

@@ -381,8 +381,10 @@ void stream_reset(stream_t *s){
 
 int stream_control(stream_t *s, int cmd, void *arg){
   if(!s->control) return STREAM_UNSUPPORTED;
+#ifdef USE_STREAM_CACHE
   if (s->cache_pid)
     return cache_do_control(s, cmd, arg);
+#endif
   return s->control(s, cmd, arg);
 }