[SDL] possible cause for Mix_PlayMusic() crashing

[James Barrett]

I think I found the issue. There is a divide by zero happening in
music.c,  function Mix_FadeInMusicPos()

line 870: music->fade_steps = ms/ms_per_step;

ms == 0
ms_per_step == 0

In the debugger, the above code gets executed before function
open_music() which sets the variable ms_per_step.


To fix the divide by zero crash, I added code just before the division
calculation:

    //Barrett 12/24/2007
    if(ms_per_step == 0)
    {
        ms_per_step = 1;
    }

Now the program no longer crashes, but my ogg music is still not
playing. I'll do more debugging later.
For all I know, setting ms_per_step to 1 might cause no playback! ;-) 
I'll have to find out why function open_music() isn't getting called
until after

Jim