Changes for Win32 port

[Corona688]

I am attempting to port SDL_sound to Win32, and so far it hasn't been
incredibly difficult.  I've started with a plain Win32 static library.

aiff.c, raw.c, voc.c and wav.c all compiled without complaint.

In ogg.c, there was one instance of int64_t that needed to be changed to
ogg_int64_t, it now compiles fine.

In shn.c, I regrettably needed to remove almost every darn inline.
Also, I had to change
    memcpy(internal->buffer + bw, shn->backBuffer, i);
into
    memcpy((char *)internal->buffer + bw, shn->backBuffer, i);
because it complained that "void * is of unknown size". It now compiles
fine.

I haven't done mp3.c, midi.c, and mod.c because I don't have the
required libraries yet, but I'm working on that...

When I compiled and used playsound.exe with SDL_sound.lib,
ogg_static.lib, vorbis_static.lib, and vorbisfile_static.lib linked in,
it worked fine with wav's, ogg's, and aif's.  It plays .VOCs, but sounds
odd; I'm uncertain as to which is the problem, the code or the .voc.
Lastly, I don't have a .shn handy to test it with so I just don't know.