http://www.slowass.net/user/scott/gmodplay-0.08-fixed-20041215.tgz is a fixed version of gmodplay-0.08. The fixes were pretty trivial but it took a while to dig into it all and I thought maybe myself and Google could save the next poor schmuck the bother. The code was trying to say things like new struct Foo and x = (struct Foo*)something(). In these examples, gcc now doesn't tolerate the world "struct" appearing. The fact that Foo is a struct is of less than no consequence (it's apparently of negitive consequence). Perhaps there's another way to get this to build by telling gcc to ignore this. Perhaps there is a much better mod file player. I like seeing the messages written out with the instrument names, though. There are a few formats I see commonly that gmodplay can't play, but with its modplug engine, it does better than most trackers.
-scott