Fix smpeg compilation

src/smpeg-0-fix-missing-declaration.patch

@@ -0,0 +1,18 @@
+--- ./MPEGaudio.h~	2006-03-13 15:24:38.000000000 +0000
++++ ./MPEGaudio.h	2006-03-13 15:25:07.000000000 +0000
+@@ -149,6 +149,14 @@
+ };
+ 
+ /* The actual MPEG audio class */
++
++class MPEGaudio;
++void Play_MPEGaudioSDL(void *udata, Uint8 *stream, int len);
++int Play_MPEGaudio(MPEGaudio *audio, Uint8 *stream, int len);
++#ifdef THREADED_AUDIO
++int Decode_MPEGaudio(void *udata);
++#endif
++
+ class MPEGaudio : public MPEGerror, public MPEGaudioaction {
+ 
+     friend void Play_MPEGaudioSDL(void *udata, Uint8 *stream, int len);
+