When loading music, STK prints a warning if the file format is not recognized.

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/trunk/supertuxkart@1289 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/sound_manager.cpp

@@ -179,6 +179,7 @@ void SoundManager::playMusic(const char* filename)
 
 #endif
         if(m_current_music == NULL)	// no support for file
+            fprintf(stderr, "WARNING: music file %s format not recognized.\n", filename);
             return;
 
             if((m_current_music->load(filename)) == false)